Disc cartridge

ABSTRACT

A disc cartridge includes: a disc storage portion; first and second shutters provided on the bottom of the disc storage portion; and a rotational member interlocked with the shutters and having a disc supporting portion to support the disc thereon while the shutters are closed and a notch to be located inside a head opening while the shutters are opened. The shutters include disc holders for holding the disc thereon with the center of the disc offset from that of the disc storage portion such that an outer side surface of the disc contacts with the sidewall of the disc storage portion at a position where the notch is located while the shutters are closed. The inner circumference of a region, where the disc supporting portion contacts with the second side of the disc, defines a circle that has its center offset from the center of the disc storage portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. patent application Ser. No.10/450,738, filed Jun. 17, 2003 now U.S. Pat. No. 6,971,117 which was aSection 371 of International Application No. PCT/JP02/11630, filed Nov.7, 2002.

BACKGROUND OF THE INVENTION

The present invention relates to a disc cartridge for use to store adisk storage medium such as an optical disc or a magnetic disk thereinin a rotatable state.

Various disc cartridges have been proposed as protective cases for discstorage media.

For example, Japanese Laid-Open Publication No. 9-153264 discloses adisc cartridge in which a disk storage medium having a single or doublesignal recording sides (which will be herein referred to as a “disc”simply) is completely enclosed in a disc storage portion. The discstorage portion is defined inside a cartridge body that is made up ofupper and lower halves. The cartridge body includes chucking openingsand a head opening. The chucking openings allow the turntable of aspindle motor and a damper to chuck a disc inserted, while the headopening allows a read/write head to read and/or write a signal from/onthe disc. The lower one of the chucking openings is continuous with thehead opening. Accordingly, while the user carries such a cartridge, dusteasily enters the inside of the cartridge through these openings and thedisc is also easily soiled with finger marks. For that reason, the disccartridge further includes a shutter for closing these openings up.

A disc cartridge having such a structure, however, has the followingdrawbacks. Firstly, such a disc cartridge cannot be so thin. This isbecause the disc storage space, defined between the upper and lowerhalves, should be thick enough to allow a disc drive to accurately reador write a signal (or information) from/onto the disc stored in such adisc cartridge. The reasons why the disc storage space should berelatively thick include the expected flutter or warp of the disc beingrotated and an error that may occur in disposing the disc cartridge at apredetermined position inside the disc drive.

Secondly, the shutter for closing up these chucking and head openings atthe same time cannot be formed at a low cost, thus increasing theoverall manufacturing cost of such a disc cartridge. The reason is asfollows. Specifically, the lower half of the disc cartridge is providedwith a chucking opening for the turntable of the spindle motor and ahead opening, while the upper half thereof is provided with anotherchucking opening for the clamper. Thus, to close these three openings upat a time, the shutter needs to be formed in a U-shape, which is not socheap to make.

Thirdly, the disc stored inside such a disc cartridge is not fixed inmany cases, thus possibly causing dust or fine particle deposition andscratching problems. Specifically, although a disc with a metal hub canbe attracted and fixed in position via a magnetic force so as not tomove inconstantly, an optical disc with no hub, e.g., a CD or a DVD, isnormally not fixed, and movable freely, inside the disc cartridge.Accordingly, when the shutter of the disc cartridge is opened inside thedisc drive, dust may enter the cartridge through its openings and bedeposited on the disc easily. Also, if the disc is shaken so much as tocontact with the inner walls of the disc cartridge, the signal recordingside of the disc may get scratched or fine particles may be stirred upand deposited on the disc.

BRIEF SUMMARY OF THE INVENTION

In order to overcome the problems described above, an object of thepresent invention is to provide a disc cartridge that has a reducedthickness and a simplified, much less expensive shutter for asingle-sided disc, in particular.

Another object of the present invention is to provide a disc cartridgethat can drastically reduce the dust to be deposited on the disc storedtherein by getting the disc firmly held inside the disc cartridge andeliminating the inconstant movement of the disc.

A third object of the present invention is to provide a disc cartridgeof a good design by displaying the label side of the disc storedtherein.

A disc cartridge according to a preferred embodiment of the presentinvention preferably includes a cartridge body, first and secondshutters, and a rotational member. The cartridge body preferablyincludes a disc storage portion, a chucking opening and a head opening.The disc storage portion preferably has a disc window and a bottom andpreferably stores a disc, having first and second sides, therein so thatthe disc is rotatable in the disc storage portion and that the firstside of the disc is exposed inside the disc window. The chucking openingis preferably formed on the bottom of the disc storage portion so as toget the disc chucked externally. The head opening is also preferablyformed on the bottom of the disc storage portion so as to allow a head,which reads and/or writes a signal from on the second side of the disc,to access the second side of the disc. The first and second shutters arepreferably provided on the bottom of the disc storage portion for thepurpose of exposing or covering the head opening. The rotational memberis preferably provided over the first and second shutters inside thedisc storage portion and preferably rotates as the first and secondshutters are opened or closed. The rotational member preferably includesa disc supporting portion and a notch. The disc supporting portionpreferably contacts with an outer periphery of the second side of thedisc while the first and second shutters are closed and thereby holdsthe disc thereon. The notch is preferably provided for the discsupporting portion so as to be located inside the head opening while thefirst and second shutters are opened. The disc storage portionpreferably includes a sidewall along an outer periphery of the bottom.The first and second shutters preferably include disc holders forholding the disc thereon with the center of the disc offset from thecenter of the disc storage portion such that an outer side surface ofthe disc contacts with the sidewall of the disc storage portion at aposition where the notch of the rotational member is located while thefirst and second shutters are closed. The inner circumference of aregion, in which the disc supporting portion of the rotational membercontacts with the second side of the disc, preferably defines a circlethat has its center offset from the center of the disc storage portion.

In one preferred embodiment of the present invention, while the firstand second shutters are closed, the center of the disc is preferablyaligned with the center of the circle.

In another preferred embodiment of the present invention, while thefirst and second shutters are closed, a distance between the center ofthe disc and the center of the disc storage portion is preferably about0.5 mm to about 1.5 mm.

In still another preferred embodiment, a portion of the sidewall of thedisc storage portion, which contacts with the outer side surface of thedisc, preferably has a radius of curvature that is substantially equalto that of the disc.

In yet another preferred embodiment, the other portion of the sidewallof the disc storage portion, which does not contact with the outer sidesurface of the disc, preferably has a radius of curvature that isgreater than that of the disc.

A disc cartridge according to another preferred embodiment of thepresent invention preferably includes a cartridge body, first and secondshutters, and a rotational member. The cartridge body preferablyincludes a disc storage portion, a chucking opening and a head opening.The disc storage portion preferably has a disc window and a bottom andpreferably stores a disc, having first and second sides, therein so thatthe disc is rotatable in the disc storage portion and that the firstside of the disc is exposed inside the disc window. The chucking openingis preferably formed on the bottom of the disc storage portion so as toget the disc chucked externally. The head opening is also preferablyformed on the bottom of the disc storage portion so as to allow a head,which reads and/or writes a signal from/on the second side of the disc,to access the second side of the disc. The first and second shutters arepreferably provided on the bottom of the disc storage portion for thepurpose of exposing or covering the head opening. The rotational memberis preferably provided over the first and second shutters inside thedisc storage portion and preferably rotates as the first and secondshutters are opened or closed. The rotational member preferably includesa disc supporting portion and a notch. The disc supporting portionpreferably contacts with an outer periphery of the second side of thedisc while the first and second shutters are closed and thereby holdsthe disc thereon. The notch is preferably provided for the discsupporting portion so as to be located inside the head opening while thefirst and second shutters are opened. The disc storage portionpreferably includes a sidewall along an outer periphery of the bottom.One of the first and second shutters preferably includes a disc holderfor applying an elastic force to the disc and holding the disc thereonsuch that an outer side surface of the disc contacts with the sidewallof the disc storage portion at a position where the notch of therotational member is located while the first and second shutters areclosed. The elastic force is preferably applied to the disc by deformingelastically the first or second shutter that includes the disc holder.

In one preferred embodiment of the present invention, the cartridge bodypreferably includes a recessed portion on the bottom of the disc storageportion. The first or second shutter that includes the disc holder ispreferably deformed elastically near a sidewall that defines therecessed portion.

A disc cartridge according to still another preferred embodiment of thepresent invention preferably includes a cartridge body, at least oneshutter, and a disc stopper. The cartridge body preferably includes adisc storage portion, a chucking opening and a head opening. The discstorage portion preferably has a disc window and a bottom and preferablystores a disc, having first and second sides, therein so that the discis rotatable in the disc storage portion and that the first side of thedisc is exposed inside the disc window. The chucking opening ispreferably formed on the bottom of the disc storage portion so as to getthe disc chucked externally. The head opening is also preferably formedon the bottom of the disc storage portion so as to allow a head, whichreads and/or writes a signal from/on the second side of the disc, toaccess the second side of the disc. The shutter is preferably providedon the bottom of the disc storage portion for the purpose of exposing orcovering the head opening. The disc stopper preferably has an archedconcave side surface and is preferably supported by the cartridge bodyso as to be movable from a first position, at which the arched concaveside surface protrudes over the disc that is stored inside the discstorage portion, to a second position, at which the arched concave sidesurface is not located over the disc, or vice versa.

In one preferred embodiment of the present invention, the arched concaveside surface of the disc stopper preferably extends along a longer sideof the disc stopper. The disc stopper may move from the first positionto the second position, or vice versa, by sliding vertically to thelonger side with respect to the cartridge body.

In an alternative preferred embodiment, the arched concave side surfaceof the disc stopper preferably extends along a longer side of the discstopper. The disc stopper may move from the first position to the secondposition, or vice versa, by rotating on a shaft that extends parallellyto the longer side.

In another alternative preferred embodiment, the arched concave sidesurface of the disc stopper preferably extends along a longer side ofthe disc stopper. The disc stopper may move from the first position tothe second position, or vice versa, by rotating on a shaft substantiallyparallelly to the first side of the disc. In that case, the shaft ispreferably provided near one end of the longer side of the disc stopper.

In this particular preferred embodiment, the other end of the longerside of the disc stopper may be engaged with the cartridge body.

A disc cartridge according to yet another preferred embodiment of thepresent invention preferably includes a cartridge body, at least oneshutter, a removal history hole, a cap member, and a disc stopper. Thecartridge body preferably includes a disc storage portion, a chuckingopening and a head opening. The disc storage portion preferably has adisc window and a bottom and preferably stores a disc, having first andsecond sides, therein so that the disc is rotatable in the disc storageportion and that the first side of the disc is exposed inside the discwindow. The chucking opening is preferably formed on the bottom of thedisc storage portion so as to get the disc chucked externally. The headopening is also preferably formed on the bottom of the disc storageportion so as to allow a head, which reads and/or writes a signalfrom/on the second side of the disc, to access the second side of thedisc. The shutter is preferably provided on the bottom of the discstorage portion for the purpose of exposing or covering the headopening. The removal history hole is preferably provided for thecartridge body. The cap member preferably covers the removal historyhole at least partially. The disc stopper is preferably supported by thecartridge body so as to be movable from a first position, at which thedisc stopper protrudes over the disc that is stored inside the discstorage portion, to a second position, at which the disc stopper is notlocated over the disc, or vice versa. While the disc stopper is movingfrom the first position to the second position, the disc stopperpreferably removes the cap member from the removal history hole.

In one preferred embodiment of the present invention, the disc stopperpreferably moves from the first position to the second position, or viceversa, by rotating on a shaft substantially parallelly to the first sideof the disc. The shaft is preferably provided near one end of the longerside of the disc stopper thereof. The center of rotation of the discstopper is preferably aligned with the center of the removal historyhole.

In this particular preferred embodiment, the cap member preferably has acolumnar shape and preferably includes: connectors that are connected toan inner sidewall of the removal history hole; and a convex portion toengage with the disc stopper. The disc stopper preferably includes aconcave portion that engages with the convex portion of the cap member.

More particularly, the center of the concave portion of the disc stopperis preferably aligned with the center of rotation of the disc stopper.By rotating the disc stopper, the cap member is rotated, the connectorsare snapped off, and the cap member drops off from the removal historyhole.

A disc cartridge according to yet another preferred embodiment of thepresent invention preferably includes a cartridge body, first and secondshutters, a rotational member and a disc holder. The cartridge bodypreferably includes a disc storage portion, a chucking opening and ahead opening. The disc storage portion preferably has a disc window anda bottom and preferably stores a disc, having first and second sides,therein so that the disc is rotatable in the disc storage portion andthat the first side of the disc is exposed inside the disc window. Thechucking opening is preferably formed on the bottom of the disc storageportion so as to get the disc chucked externally. The head opening isalso preferably formed on the bottom of the disc storage portion so asto allow a head, which reads and/or writes a signal from/on the secondside of the disc, to access the second side of the disc. The first andsecond shutters are preferably provided on the bottom of the discstorage portion for the purpose of exposing or covering the headopening. The rotational member is preferably provided over the first andsecond shutters inside the disc storage portion and is preferablyinterlocked with the first and second shutters in such a manner as toopen or close the first and second shutters when rotates inside the discstorage portion. The disc holder preferably holds the disc thereon so asnot to contact with a signal recording area on the second side of thedisc while the first and second shutters are closed.

In one preferred embodiment of the present invention, supposing that adistance from the center of the disc to a first point on the second sideof the disc is Rin; a distance from the center of the disc to a secondpoint on the second side of the disc is Rout; a space having a height Sneeds to be provided under the second side of the disc; a first circlehaving a radius of Rout is defined on the second side of the disc; asecond circle having a radius of (Rout—1.2 S) is defined on a plane thatis separated from the second side by a distance of 0.3 S and parallel tothe second side; and a third circle having a radius of (Rout—16.2 S) isdefined on a plane that is separated from the second side by thedistance S and parallel to the second side, the space is preferablyobtained by removing a circular cylinder, having a bottom radius of Rinas measured from the center of the disc and the height S, from first andsecond truncated cones. The first point is located closer to the centerof the disc than, and defined near, the inner periphery of the signalrecording area while the first and second shutters are closed. Thesecond point is located closer to an outer edge of the disc than, anddefined near, the outer periphery of the signal recording area while thefirst and second shutters are closed. The bottom and top of the firsttruncated cone are defined by the first and second circles,respectively, while the bottom and top of the second truncated cone aredefined by the second and third circles, respectively.

In this particular preferred embodiment, the height S of the space ispreferably 1 mm, the bottom radius Rin of the circular cylinder ispreferably 20 mm, and the radius Rout of the first circle is preferably59 mm.

In another preferred embodiment, the rotational member preferablyincludes a disc supporting portion and a notch. The disc supportingportion preferably contacts with an outer periphery of the second sideof the disc while the first and second shutters are closed and therebyholds the disc thereon. The notch is preferably provided for the discsupporting portion so as to be located inside the head opening while thefirst and second shutters are opened. The disc storage portionpreferably includes a sidewall along an outer periphery of the bottom.The disc holder preferably holds the disc thereon with the center of thedisc offset from the center of the disc storage portion such that anouter side surface of the disc contacts with the sidewall of the discstorage portion at a position where the notch of the rotational memberis located while the first and second shutters are closed.

In this particular preferred embodiment, the disc supporting portion ofthe rotational member is preferably located at such a position as not toobstruct the space while the first and second shutters are closed.

In another preferred embodiment, the inner circumference of a region, inwhich the disc supporting portion of the rotational member contacts withthe second side of the disc, preferably defines a circle that has itscenter offset from the center of the disc storage portion.

More particularly, while the first and second shutters are closed, thecenter of the disc is preferably aligned with the center of the circle.

In still another preferred embodiment, while the first and secondshutters are closed, a distance between the center of the disc and thecenter of the disc storage portion is preferably about 0.5 mm to about1.5 mm.

A disc cartridge according to yet another preferred embodiment of thepresent invention preferably includes a cartridge body, first and secondshutters, a rotational member and a disc holder. The cartridge bodypreferably includes a disc storage portion, a chucking opening and ahead opening. The disc storage portion preferably has a disc window anda bottom and preferably stores a disc, having first and second sides,therein so that the disc is rotatable in the disc storage portion andthat the first side of the disc is exposed inside the disc window. Thechucking opening is preferably formed on the bottom of the disc storageportion so as to get the disc chucked externally. The head opening isalso preferably formed on the bottom of the disc storage portion so asto allow a head, which reads and/or writes a signal from/on the secondside of the disc, to access the second side of the disc. The first andsecond shutters are preferably provided on the bottom of the discstorage portion for the purpose of exposing or covering the headopening. The rotational member is preferably provided over the first andsecond shutters inside the disc storage portion and is preferablyinterlocked with the first and second shutters in such a manner as toopen or close the first and second shutters when rotates inside the discstorage portion. The disc holder preferably holds the disc thereon insuch a manner as not to contact with a clamp area, which is provided onthe second side of the disc, while the first and second shutters areclosed.

In this particular preferred embodiment, the disc holder holds the discin such a manner as not to contact with protruding ring provided on thesecond side of the disc in the vicinity clamp area. Further, when thefirst and second shutters are closed, the disc holder holds the disc insuch a manner as not to contact with neither a clamp area nor a regionwhich is located between the clamp area and the center hole and which isapart from the edge of the center hole by 0.1 mm or more or in such amanner as not to contact with neither a clamp area nor a region which islocated between the clamp area and the signal recording area and whichis apart from the edge of the clamp area by 2 mm or less.

A disc cartridge according to yet another preferred embodiment of thepresent invention preferably includes a cartridge body, first and secondshutters, and a rotational member. The cartridge body preferablyincludes a disc storage portion, a chucking opening and a head opening.The disc storage portion preferably has a disc window and a bottom andpreferably stores a disc, having first and second sides, therein so thatthe disc is rotatable in the disc storage portion and that the firstside of the disc is exposed inside the disc window. The chucking openingis preferably formed on the bottom of the disc storage portion so as toget the disc chucked externally. The head opening is also preferablyformed on the bottom of the disc storage portion so as to allow a head,which reads and/or writes a signal from on the second side of the disc,to access the second side of the disc. The first and second shutters arepreferably provided on the bottom of the disc storage portion for thepurpose of exposing or covering the head opening. The rotational memberis preferably provided over the first and second shutters inside thedisc storage portion and is preferably interlocked with the first andsecond shutters in such a manner as to open or close the first andsecond shutters when rotates inside the disc storage portion. The firstand second shutters preferably have first and second pairs of contactportions in two separate regions. The contact portions of each of thefirst and second pairs preferably contact and overlap with each other ina thickness direction. An order in which the contact portions of thefirst pair overlap with each other is preferably reverse to an order inwhich the contact portions of the second pair overlap with each other.

In one preferred embodiment of the present invention, the first andsecond shutters preferably further include a sidewall, which stands inthe vicinity of the first pair of contact portions, and a third pair ofcontact portions. The third pair of contact portions preferably contactsand overlaps with each other in the thickness direction over thesidewall. One of the two contact portions of the first pair and one ofthe two contact portions of the third pair of the first or secondshutter preferably contact with, and sandwich, the other contact portionof the first pair and the other contact portion of the third pair of thesecond or first shutter.

A disc cartridge according to yet another preferred embodiment of thepresent invention preferably includes a cartridge body, first and secondshutters, and a rotational member. The cartridge body preferablyincludes a disc storage portion, a chucking opening and a head opening.The disc storage portion preferably has a disc window and a bottom andpreferably stores a disc, having first and second sides, therein so thatthe disc is rotatable in the disc storage portion and that the firstside of the disc is exposed inside the disc window. The chucking openingis preferably formed on the bottom of the disc storage portion so as toget the disc chucked externally. The head opening is also preferablyformed on the bottom of the disc storage portion so as to allow a head,which reads and/or writes a signal from/on the second side of the disc,to access the second side of the disc. The first and second shutters arepreferably provided on the bottom of the disc storage portion for thepurpose of exposing or covering the head opening. The rotational memberis preferably provided over the first and second shutters inside thedisc storage portion and is preferably interlocked with the first andsecond shutters in such a manner as to open or close the first andsecond shutters when rotates inside the disc storage portion. The firstand second shutters closed preferably contact with each other to definea hole in a region corresponding to a center hole of the disc. A contactportion of one of the first and second shutters preferably includes aconvex portion around the hole, while a contact portion of the othershutter preferably includes a concave portion, which engages with theconvex portion, around the hole.

A disc cartridge according to yet another preferred embodiment of thepresent invention preferably includes a cartridge body, first and secondshutters, and a rotational member. The cartridge body preferablyincludes a disc storage portion, a chucking opening and a head opening.The disc storage portion preferably has a disc window and a bottom andpreferably stores a disc, having first and second sides, therein so thatthe disc is rotatable in the disc storage portion and that the firstside of the disc is exposed inside the disc window. The chucking openingis preferably formed on the bottom of the disc storage portion so as toget the disc chucked externally. The head opening is also preferablyformed on the bottom of the disc storage portion so as to allow a head,which reads and/or writes a signal from/on the second side of the disc,to access the second side of the disc. The first and second shutters arepreferably provided on the bottom of the disc storage portion for thepurpose of exposing or covering the head opening. The rotational memberis preferably provided over the first and second shutters inside thedisc storage portion and is preferably interlocked with the first andsecond shutters in such a manner as to open or close the first andsecond shutters when rotates inside the disc storage portion. The firstand second shutters preferably include a plurality of disc holders thatcontacts with an outer side surface of the disc and its surroundportions and that holds the disc thereon while the first and secondshutters are closed. The rotational member preferably includes asidewall that contacts with at least one of the disc holders in such amanner as to prevent the at least one disc holder from being deformed ina radial direction of the disc while the first and second shutters areclosed.

A disc cartridge according to yet another preferred embodiment of thepresent invention preferably includes a cartridge body, first and secondshutters, and a rotational member. The cartridge body preferablyincludes a disc storage portion, a chucking opening and a head opening.The disc storage portion preferably has a disc window and a bottom andpreferably stores a disc, having first and second sides, therein so thatthe disc is rotatable in the disc storage portion and that the firstside of the disc is exposed inside the disc window. The chucking openingis preferably formed on the bottom of the disc storage portion so as toget the disc chucked externally. The head opening is also preferablyformed on the bottom of the disc storage portion so as to allow a head,which reads and/or writes a signal from/on the second side of the disc,to access the second side of the disc. The first and second shutters arepreferably provided on the bottom of the disc storage portion for thepurpose of exposing or covering the head opening. The rotational memberis preferably provided over the first and second shutters inside thedisc storage portion and is preferably interlocked with the first andsecond shutters in such a manner as to open or close the first andsecond shutters when rotates inside the disc storage portion. Thecartridge body preferably includes a rim, which is provided on thebottom of the disc storage portion so as to surround the chucking andhead openings. The first and second shutters preferably includerespective concave portions on their back surfaces, which are opposed tothe bottom of the disc storage portion, to receive the rim.

A disc cartridge according to yet another preferred embodiment of thepresent invention preferably includes a cartridge body, first and secondshutters, and a rotational member. The cartridge body preferablyincludes a disc storage portion, a chucking opening and a head opening.The disc storage portion preferably has a disc window and a bottom andpreferably stores a disc, having first and second sides, therein so thatthe disc is rotatable in the disc storage portion and that the firstside of the disc is exposed inside the disc window. The chucking openingis preferably formed on the bottom of the disc storage portion so as toget the disc chucked externally. The head opening is also preferablyformed on the bottom of the disc storage portion so as to allow a head,which reads and/or writes a signal from/on the second side of the disc,to access the second side of the disc. The first and second shutters arepreferably provided on the bottom of the disc storage portion for thepurpose of exposing or covering the head opening. The rotational memberis preferably provided over the first and second shutters inside thedisc storage portion and is preferably interlocked with the first andsecond shutters in such a manner as to open or close the first andsecond shutters when rotates inside the disc storage portion. Thecartridge body preferably includes engaging means that is selectivelyengageable with a first or second disc stopper so that each of the firstand second disc stoppers is attachable to the cartridge body. The firstdisc stopper is preferably movable from a first position, at which thefirst disc stopper protrudes partially over the disc that is storedinside the disc storage portion, to a second position, at which thefirst disc stopper is not located over the disc, or vice versa. Thesecond disc stopper is preferably fixed at the first position.

A disc cartridge according to yet another preferred embodiment of thepresent invention preferably includes a cartridge body, first and secondshutters, and a rotational member. The cartridge body preferablyincludes a disc storage portion, a chucking opening and a head opening.The disc storage portion preferably has a disc window and a bottom andpreferably stores a disc, having first and second sides, therein so thatthe disc is rotatable in the disc storage portion and that the firstside of the disc is exposed inside the disc window. The chucking openingis preferably formed on the bottom of the disc storage portion so as toget the disc chucked externally. The head opening is also preferablyformed on the bottom of the disc storage portion so as to allow a head,which reads and/or writes a signal from/on the second side of the disc,to access the second side of the disc. The first and second shutters arepreferably provided on the bottom of the disc storage portion for thepurpose of exposing or covering the head opening. The rotational memberis preferably provided over the first and second shutters inside thedisc storage portion and is preferably interlocked with the first andsecond shutters in such a manner as to open or close the first andsecond shutters when rotates inside the disc storage portion. The firstand second shutters are preferably disposed so as to be sandwichedbetween the rotational member and the bottom of the disc storageportion. The cartridge body preferably includes a raised portion, whichhas a height that is approximately equal to the thickness of the firstand second shutters, on the bottom of the disc storage portion.

A disc drive according to yet another preferred embodiment of thepresent invention is preferably loaded with the disc cartridge accordingto any of the preferred embodiments of the present invention describedabove and preferably reads and/or writes a signal from/on the disc thatis stored in the disc cartridge.

A disc drive according to yet another preferred embodiment of thepresent invention preferably includes driving means, a head, asupporting structure, and a shutter opening/closing mechanism. Thedriving means preferably rotates a disc. The head preferably readsand/or writes a signal from/on the disc. The supporting structurepreferably supports the disc cartridge according to any of the preferredembodiments of the present invention described above, which stores thedisc therein, at a predetermined position with respect to the drivingmeans. The shutter opening/closing mechanism preferably opens theshutter of the disc cartridge and gets the disc released from the discholder so that the disc is rotatable inside the disc storage portion ofthe disc cartridge.

In one preferred embodiment of the present invention, the disc drivepreferably further includes a damper for mounting the disc onto thedriving means.

In this particular preferred embodiment, the supporting structurepreferably includes a positioning pin for fixing the disc cartridge atthe predetermined position.

Other features, elements, processes, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of preferred embodiments of the presentinvention with reference to the attached drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe invention, will be better understood when read in conjunction withthe appended drawings. For the purpose of illustrating the invention,there are shown in the drawings embodiments which are presentlypreferred. It should be understood, however, that the invention is notlimited to the precise arrangements and instrumentalities shown.

In the drawings:

FIG. 1 is a perspective view illustrating an overall configuration for adisc cartridge according to a first specific preferred embodiment of thepresent invention.

FIG. 2 is a perspective view of the disc cartridge shown in FIG. 1 asviewed from below it.

FIG. 3 is an exploded perspective view of the disc cartridge shown inFIG. 1.

FIG. 4 is a cross-sectional view illustrating a disc holder and asurround portion of the disc cartridge shown in FIG. 1.

FIG. 5 is a cross-sectional view illustrating another disc holder and asurround portion of the disc cartridge shown in FIG. 1.

FIG. 6 is a perspective view illustrating a state of the disc cartridgeshown in FIG. 1 in which its shutter is opened and positioning pins havebeen inserted into its positioning holes.

FIG. 7 is a cross-sectional view illustrating a disc holder and asurround portion of the disc cartridge shown in FIG. 6.

FIG. 8 is a perspective view illustrating another disc holder and asurround portion of the disc cartridge shown in FIG. 6.

FIG. 9 is a plan view illustrating an overall configuration for a disccartridge according to a second specific preferred embodiment of thepresent invention.

FIG. 10 is a plan view illustrating a state of the disc cartridge shownin FIG. 9 in which the disc has been released from its disc holders.

FIG. 11 is a plan view illustrating an overall configuration for a disccartridge according to a third specific preferred embodiment of thepresent invention.

FIG. 12 is a plan view illustrating a state of the disc cartridge shownin FIG. 11 in which the disc has been released from its disc holders.

FIG. 13 is a plan view illustrating an overall configuration for a disccartridge according to a fourth specific preferred embodiment of thepresent invention.

FIG. 14 is a plan view illustrating a state of the disc cartridge shownin FIG. 13 in which the disc has been released from its disc holder.

FIG. 15 is a plan view illustrating an overall configuration for a disccartridge according to a fifth specific preferred embodiment of thepresent invention in a state where its shutter is closed.

FIG. 16 is a cross-sectional view of a disc holder of the disc cartridgein the state shown in FIG. 15.

FIG. 17 is a plan view illustrating an overall configuration for thedisc cartridge shown in FIG. 15 in a state where its shutter is opened.

FIG. 18 is a cross-sectional view of the disc holder of the disccartridge in the state shown in FIG. 17.

FIG. 19 is a plan view illustrating an overall configuration for a disccartridge according to a sixth specific preferred embodiment of thepresent invention in a state where its shutter is closed.

FIG. 20 is a plan view illustrating an overall configuration for thedisc cartridge shown in FIG. 19 in a state where its shutter is opened.

FIG. 21 is a plan view illustrating an overall configuration for a disccartridge according to a seventh specific preferred embodiment of thepresent invention in a state where its shutter is closed.

FIG. 22 is a plan view illustrating an overall configuration for thedisc cartridge shown in FIG. 21 in a state where its shutter is opened.

FIG. 23 is a perspective view illustrating an overall configuration fora disc cartridge according to an eighth specific preferred embodiment ofthe present invention.

FIG. 24 is an exploded perspective view of the disc cartridge shown inFIG. 23.

FIG. 25 is a perspective view illustrating the disc cartridge shown inFIG. 23 with its upper shell and the disc removed to show a state whereits shutters are closed.

FIG. 26 is a perspective view illustrating the disc cartridge shown inFIG. 23 with its upper shell and the disc removed to show a state whereits shutters are opened.

FIG. 27 is a perspective view illustrating the disc cartridge shown inFIG. 23 with the disc removed to show a state where its shutters areclosed.

FIG. 28 is a perspective view illustrating the disc cartridge shown inFIG. 23 with the disc removed to show a state where its shutters areopened.

FIG. 29 is a partial cross-sectional view of the disc cartridge shown inFIG. 23, which is viewed along a plane that passes the center of thedisc.

FIG. 30 is a cross-sectional view illustrating a portion of the shutterof the disc cartridge shown in FIG. 23.

FIG. 31 is a partial plan view illustrating a shutter opener/closer andits surrounding portion in the disc cartridge shown in FIG. 23.

FIG. 32 is a perspective view illustrating a disc stopper of the disccartridge shown in FIG. 23.

FIG. 33 is a front view illustrating the insertion side of the disccartridge shown in FIG. 23.

FIG. 34 is a perspective view illustrating an overall configuration fora disc cartridge according to a ninth specific preferred embodiment ofthe present invention.

FIG. 35 is an exploded perspective view of the disc cartridge shown inFIG. 34.

FIG. 36 is a perspective view illustrating the disc cartridge shown inFIG. 34 with the disc removed to show a state where its shutters areclosed.

FIG. 37 is a perspective view illustrating the disc cartridge shown inFIG. 34 with the disc removed to show a state where its shutters areopened.

FIG. 38 is a partial cross-sectional view of the disc cartridge shown inFIG. 34, which is viewed along a plane that passes the center of thedisc to show a state where its shutters are closed.

FIG. 39 is a partial cross-sectional view of the disc cartridge shown inFIG. 34, which is viewed along a plane that passes the center of thedisc to show a state where its shutters are opened.

FIG. 40 is a partial cross-sectional view illustrating a portion of thedisc cartridge shown in FIG. 34 around the disc outer periphery, whichis viewed along a plane passing the center of the disc to show a statewhere its shutters are closed.

FIG. 41 is a partial cross-sectional view illustrating a portion of thedisc cartridge shown in FIG. 34 around the disc outer periphery, whichis viewed along a plane passing the center of the disc to show a statewhere its shutters are opened.

FIG. 42 is a perspective view illustrating an overall configuration fora disc cartridge according to a tenth specific preferred embodiment ofthe present invention.

FIG. 43 is an exploded perspective view of the disc cartridge shown inFIG. 42.

FIG. 44 is a perspective view illustrating the disc cartridge shown inFIG. 42 with the disc removed to show a state where its shutters areclosed.

FIG. 45 is a perspective view illustrating the disc cartridge shown inFIG. 42 with the disc removed to show a state where its shutters areopened.

FIG. 46 is a partial cross-sectional view of the disc cartridge shown inFIG. 42, which is viewed along a plane that passes the center of thedisc to show a state where its shutters are closed.

FIG. 47 is a partial cross-sectional view of the disc cartridge shown inFIG. 42, which is viewed along a plane that passes the center of thedisc to show a state where its shutters are opened.

FIG. 48 is a partial cross-sectional view illustrating a portion of thedisc cartridge shown in FIG. 42 around the disc outer periphery, whichis viewed along a plane passing the center of the disc to show a statewhere its shutters are closed.

FIG. 49 is a partial cross-sectional view illustrating a portion of thedisc cartridge shown in FIG. 42 around the disc outer periphery, whichis viewed along a plane passing the center of the disc to show a statewhere its shutters are opened.

FIG. 50 is a perspective view illustrating an overall configuration fora disc cartridge according to an eleventh specific preferred embodimentof the present invention.

FIG. 51 is an exploded perspective view of the disc cartridge shown inFIG. 50.

FIG. 52 is a perspective view illustrating the disc cartridge shown inFIG. 50 with the disc removed to show a state where its shutters areclosed.

FIG. 53 is a perspective view illustrating the disc cartridge shown inFIG. 50 with the disc removed to show a state where its shutters areopened.

FIG. 54 is a partial cross-sectional view of the disc cartridge shown inFIG. 50, which is viewed along a plane that passes the center of thedisc to show a state where its shutters are closed.

FIG. 55 is a partial cross-sectional view of the disc cartridge shown inFIG. 50, which is viewed along a plane that passes the center of thedisc to show a state where its shutters are opened.

FIG. 56 is a cross-sectional view illustrating a portion of the shutterof the disc cartridge shown in FIG. 50.

FIG. 57 is a partial plan view illustrating a shutter opener/closer andits surrounding portion in the disc cartridge shown in FIG. 50.

FIG. 58 is a perspective view illustrating a disc cartridge according toa twelfth specific preferred embodiment of the present invention withthe disc removed to show a state where its shutters are closed.

FIG. 59 is a partial cross-sectional view of the disc cartridge shown inFIG. 58, which is viewed along a plane that passes the center of thedisc to show a state where its shutters are closed.

FIG. 60 is a perspective view illustrating the disc cartridge shown inFIG. 58 with the disc removed to show a state where its shutters areopened.

FIG. 61 is a partial cross-sectional view of the disc cartridge shown inFIG. 58, which is viewed along a plane that passes the center of thedisc to show a state where its shutters are opened.

FIG. 62 is a perspective view illustrating a modified example of thedisc cartridge shown in FIG. 58 with the disc removed to show a statewhere its shutters are closed.

FIG. 63 is a perspective view illustrating a modified example of thedisc cartridge shown in FIG. 58 with the disc removed to show a statewhere its shutters are opened.

FIG. 64 is a perspective view illustrating an overall configuration fora disc cartridge according to a thirteenth specific preferred embodimentof the present invention.

FIG. 65 is an exploded perspective view of the disc cartridge shown inFIG. 64.

FIG. 66 is a schematic plan view illustrating a state of the disccartridge shown in FIG. 64 in which its shutters are closed.

FIG. 67 is a schematic plan view illustrating a state of the disccartridge shown in FIG. 64 in which its shutters are opened.

FIG. 68 is a plan view illustrating the details of the shutter lockingmechanism of the disc cartridge shown in FIG. 64.

FIG. 69 is a cross-sectional view illustrating the details of the discholder of the shutter in the disc cartridge shown in FIG. 64.

FIG. 70 is a cross-sectional view illustrating the shapes of a pair ofcontact portions between the two shutters of the disc cartridge shown inFIG. 64.

FIG. 71 is a cross-sectional view illustrating the shapes of anotherpair of contact portions between the two shutters of the disc cartridgeshown in FIG. 64.

FIG. 72 is a perspective view illustrating an overall configuration fora disc cartridge according to a fourteenth specific preferred embodimentof the present invention.

FIG. 73 is a perspective view illustrating the shutters of the disccartridge shown in FIG. 72.

FIG. 74 is a perspective view illustrating the disc holders and theirsurrounding members of the disc cartridge shown in FIG. 72 to a largerscale.

FIG. 75 is a perspective view illustrating the disc holder and itssurrounding portion in the disc cartridge shown in FIG. 72 to a largerscale.

FIG. 76 is a cross-sectional view illustrating the disc holder and itssurrounding members in the disc cartridge shown in FIG. 72 to a largerscale.

FIG. 77 is a schematic plan view illustrating a state of the disccartridge shown in FIG. 72 in which its shutters are closed.

FIG. 78 is a schematic plan view illustrating a state of the disccartridge shown in FIG. 72 in which its shutters are opened.

FIG. 79 is a cross-sectional view of the disc cartridge shown in FIG. 72as viewed along the line B-B shown in FIG. 78.

FIG. 80 is a cross-sectional view of the disc cartridge shown in FIG. 72as viewed along the line C-C shown in FIG. 78.

FIG. 81 is a cross-sectional view of the disc cartridge shown in FIG. 72as viewed along the line A-A shown in FIG. 77.

FIG. 82 is a cross-sectional view illustrating a modified example of thedisc supporting portion.

FIG. 83 is an exploded perspective view of a disc cartridge according toa fifteenth specific preferred embodiment of the present invention.

FIG. 84 is a schematic plan view illustrating a state of the disccartridge shown in FIG. 83 in which its shutters are closed.

FIG. 85 is a schematic plan view illustrating a state of the disccartridge shown in FIG. 83 in which its shutters are opened.

FIG. 86 is a cross-sectional view of the disc cartridge shown in FIG. 83as viewed along the line D-D shown in FIG. 84.

FIG. 87 is a cross-sectional view of the disc cartridge shown in FIG. 83as viewed along the line E-E shown in FIG. 85.

FIG. 88 is a perspective view illustrating an overall configuration fora disc cartridge according to a sixteenth specific preferred embodimentof the present invention.

FIG. 89 is an exploded perspective view of the disc cartridge shown inFIG. 88.

FIG. 90 is a schematic plan view illustrating a state of the disccartridge shown in FIG. 88 in which its shutters are closed.

FIG. 91 is a schematic plan view illustrating a state of the disccartridge shown in FIG. 88 in which its shutters are opened.

FIG. 92 is a schematic plan view illustrating a modified example of thedisc cartridge shown in FIG. 88 in which its shutters are closed.

FIG. 93 is a schematic plan view illustrating a state of the disccartridge shown in FIG. 92 in which its shutters are opened.

FIG. 94 is a perspective view illustrating an overall configuration fora disc cartridge according to a seventeenth specific preferredembodiment of the present invention.

FIG. 95 is an exploded perspective view of the disc cartridge shown inFIG. 94.

FIG. 96 is a schematic plan view illustrating a state of the disccartridge shown in FIG. 94 in which its shutters are closed.

FIG. 97 is a schematic plan view illustrating a state of the disccartridge shown in FIG. 94 in which its shutters are opened.

FIG. 98 is a perspective view illustrating an overall configuration fora disc cartridge according to an eighteenth specific preferredembodiment of the present invention.

FIG. 99 is an exploded perspective view of the disc cartridge shown inFIG. 98.

FIG. 100 is a schematic plan view illustrating a state of the disccartridge shown in FIG. 98 in which its shutters are closed.

FIG. 101 is a schematic plan view illustrating a state of the disccartridge shown in FIG. 98 in which its shutters are opened.

FIG. 102 is an exploded perspective view of a disc cartridge accordingto a nineteenth specific preferred embodiment of the present invention.

FIG. 103 is a cross-sectional view illustrating a disc holder and itssurrounding members in the disc cartridge shown in FIG. 102 to a largerscale.

FIG. 104 is an exploded perspective view of a disc cartridge accordingto a twentieth specific preferred embodiment of the present invention.

FIG. 105 is a plan view illustrating the disc cartridge shown in FIG.104 with its upper shell removed.

FIG. 106 is a cross-sectional view of the disc cartridge shown in FIG.104 as viewed along the line F-F shown in FIG. 105.

FIG. 107 is a plan view illustrating the shutters and rotational memberof the disc cartridge shown in FIG. 104 in a state where the shuttersare closed.

FIG. 108 is a cross-sectional view of the disc cartridge shown in FIG.104 as viewed along the line G-G shown in FIG. 107.

FIG. 109 is a plan view illustrating the shutters and rotational memberof the disc cartridge shown in FIG. 104 in a state where the shuttersare opened.

FIG. 110 is a cross-sectional view of the disc cartridge shown in FIG.104 as viewed along the line H-H shown in FIG. 109.

FIG. III is a perspective view illustrating the shielding member of thedisc cartridge shown in FIG. 104.

FIG. 112 is a cross-sectional view illustrating how the shielding membershown in FIG. 111 is supported by the upper shell.

FIG. 113 is a cross-sectional view illustrating the end of the shieldingmember in a state where the shutters are closed.

FIG. 114 is a cross-sectional view illustrating the center of theshielding member in a state where the shutters are closed.

FIG. 115 is a cross-sectional view illustrating the end of the shieldingmember in a state where the shutters are opened.

FIG. 116 is a cross-sectional view illustrating the center of theshielding member in a state where the shutters are opened.

FIG. 117 is a schematic plan view illustrating a modified example of thedisc cartridge shown in FIG. 104.

FIG. 118 is a schematic plan view illustrating another modified exampleof the disc cartridge shown in FIG. 104.

FIG. 119 is an exploded perspective view of a disc cartridge accordingto a twenty-first specific preferred embodiment of the presentinvention.

FIG. 120 is a perspective view illustrating a removal history hole andits surrounding members in the disc cartridge shown in FIG. 119 to alarger scale.

FIG. 121 is a plan view of the disc cartridge shown in FIG. 119.

FIG. 122 is a cross-sectional view illustrating portions of the disccartridge shown in FIG. 119 around the shaft of the disc stopper asviewed along the line J-J shown in FIG. 121.

FIG. 123 is a cross-sectional view illustrating portions of the disccartridge shown in FIG. 119 around a latching portion of the discstopper as viewed along the line J-J shown in FIG. 121.

FIG. 124 is a cross-sectional view illustrating portions of the disccartridge shown in FIG. 119 as viewed along the line K-K shown in FIG.121.

FIG. 125 is a plan view illustrating a state of the disc cartridge shownin FIG. 119 in which the disc stopper has been disengaged.

FIG. 126 is a cross-sectional view illustrating respective portions ofthe disc cartridge shown in FIG. 119 around the shaft of the discstopper as viewed along the line J-J shown in FIG. 125.

FIG. 127 is a cross-sectional view illustrating respective portions ofthe disc cartridge shown in FIG. 119 around a latching portion of thedisc stopper as viewed along the line J-J shown in FIG. 125.

FIGS. 128 and 129 are plan views schematically illustrating a modifiedexample of the disc cartridge shown in FIG. 119.

FIGS. 130 and 131 are plan views schematically illustrating anothermodified example of the disc cartridge shown in FIG. 119.

FIG. 132 is a plan view illustrating a disc cartridge according to atwenty-second specific preferred embodiment of the present invention.

FIG. 133 is a cross-sectional view of the disc cartridge as viewed alongthe line L-L shown in FIG. 132.

FIG. 134 is a cross-sectional view illustrating a portion of the disccartridge, as viewed along the line L-L shown in FIG. 132, to a largerscale.

FIG. 135 is a plan view schematically illustrating a portion of the disccartridge shown in FIG. 132 to a larger scale.

FIGS. 136 and 137 are cross-sectional views illustrating another portionof the disc cartridge, as viewed along the line L-L shown in FIG. 132,to a larger scale.

FIG. 138 is a cross-sectional view illustrating a space to be providedunder the disc for a disc cartridge according to a twenty-third specificpreferred embodiment of the present invention.

FIG. 139 is a cross-sectional view illustrating the flexure of the disc.

FIG. 140 is a cross-sectional view illustrating another exemplary spaceto be provided under the disc.

FIG. 141 is a cross-sectional view illustrating yet another exemplaryspace to be provided under the disc.

FIG. 142 is a plan view illustrating the disc cartridge of thetwenty-third preferred embodiment of the present invention.

FIG. 143 is a cross-sectional view of the disc cartridge as viewed alongthe line P-P shown in FIG. 142.

FIG. 144 is an exploded perspective view of the disc cartridge shown inFIG. 142.

FIG. 145 is a plan view of the disc cartridge shown in FIG. 144.

FIGS. 146A and 146B are cross-sectional views of the first and secondshutters of the disc cartridge shown in FIG. 145 as viewed along thelines N-N and O-O, respectively.

FIG. 147 is a perspective view illustrating respective portions of thefirst and second shutters of the disc cartridge shown in FIG. 145 to alarger scale.

FIG. 148 is a cross-sectional view of the disc cartridge as viewed alongthe line M-M shown in FIG. 145.

FIG. 149 is a perspective view illustrating respective portions of thefirst and second shutters of the disc cartridge shown in FIG. 145 to alarger scale.

FIG. 150 is a cross-sectional view illustrating another modified exampleof the disc cartridge shown in FIG. 145.

FIG. 151 is a perspective view illustrating main parts of a disc driveaccording to a twenty-fourth specific preferred embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION Embodiment 1

Hereinafter, a disc cartridge 301 according to a first specificpreferred embodiment of the present invention will be described withreference to FIGS. 1, 2 and 3. FIG. 1 is a perspective view illustratingan overall configuration of the disc cartridge 301, including a disc 100stored, as viewed from above the cartridge 301. FIG. 2 is a perspectiveview of the disc cartridge 301 as viewed from below the cartridge 301.FIG. 3 is an exploded perspective view illustrating respective parts ofthe disc cartridge 301.

The disc 100 includes first and second sides. The first side of the disc100, on which its label, for example, is normally printed, isillustrated in FIG. 1, while the second side thereof, i.e., the signalrecording side 100A, is illustrated as the backside in FIG. 3.

As shown in FIG. 1, the disc cartridge 301 includes a lower shell 11, anupper shell 12, disc holders 13, 14 and a shutter 21.

As shown in FIG. 3, the lower shell 11 includes a chucking opening 11 cand a head opening 11 h. The chucking opening 11 c allows a chuckingmember (e.g., a spindle motor for rotating the disc 100) to enter thedisc cartridge 301 externally. The head opening 11 h allows a head,which reads and/or writes a signal from/on the signal recording side100A of the disc 100, to enter the disc cartridge 301 and access atarget location on the disc 100. The lower shell 11 also includes twopositioning holes 11 w, which engage with cartridge positioning pins 210of a disc drive (not shown), thereby fixing the disc cartridge 301 inits predetermined position inside the disc drive. The lower shell 11faces the signal recording side 100A of the disc 100.

The upper shell 12 includes a circular disc window 12 w, through whichthe disc 100 can be introduced and removed into/from the disc cartridge301 and which expands over the entire projection area of the disc 100 toexpose the upper side of the disc 100. The upper and lower shells 12 and11 are adhered or welded together at their outer periphery, therebyforming a cartridge body 10.

A disc storage portion 10 d for storing the disc 100 therein (seeFIG. 1) is defined by an inner lower surface 11 u and an inner sidesurface 12 i of the cartridge body 10. The inner lower surface 11 u isopposed to the signal recording side 100A of the disc 100, while theinner side surface 12 i has a substantially cylindrical shape anddefines the disc window 12 w inside. That is to say, the inner lowersurface 11 u is the bottom of the disc storage portion 10 d. The innerlower surface 11 u is covered with a protective layer 11 p for thepurpose of preventing the signal recording side 100A of the disc 100from getting scratched or attracting dust.

The protective layer 11 p may be appropriately selected from the groupconsisting of anti-scratching nonwoven fabric, dustproof nonwovenfabric, anti-scratching coating and dustproof coating. In this preferredembodiment, a sheet of a dustproof nonwoven fabric is adhered orultrasonic welded as the protective layer 11 p to the inner lowersurface 11 u.

In the disc storage portion 10 d, a gap, which is wide enough to allowthe disc 100 to rotate freely, is provided between the inner sidesurface 12 i and the outer periphery of the disc 100. Also, the top ofthe disc storage portion 10 d is the disc window 12 w so that the disc100 stored in the disc storage portion 10 d has one of its sides exposedinside the disc window 12 w.

As shown in FIG. 3, the disc cartridge 301 includes two disc holders 13of the same shape. Each of the disc holders 13 includes a pair ofelastic portions 13 d and a hole 13 w that runs obliquely through thedisc holder 13. When the elastic portions 13 d of the disc holders 13are sandwiched between the upper and lower shells 12 and 11, an elasticforce is applied to the respective inner ends of the disc holders 13 inthe direction indicated by the arrows 13B in FIG. 3. As a result, thedisc 100 is pressed against the inner lower surface 11 u. Also, thesetwo disc holders 13 are disposed so that the holes 13 w thereof arelocated substantially over the positioning holes 11 w.

The other disc holder 14 includes a shaft 14 s and two elastic portions14 d. The disc holder 14 is secured to the cartridge body 10 so as torotate on the shaft 14 s. When the elastic portions 14 d of the discholder 14 are sandwiched between the upper and lower shells 12 and 11,an elastic force is applied to the respective inner ends of the discholder 14 in the direction indicated by the arrow 14B in FIG. 1. As aresult, the disc 100 is pressed against the inner lower surface 11 u.

The shutter 21 is externally fitted with the lower shell 11 so as toface the signal recording side 100A of the disc 100. As shown in FIGS. 1and 2, when the shutter 21 is moved horizontally in the directionindicated by the arrow 21A or 21B, the chucking opening 11 c and thehead opening 11 h are exposed or covered. A shutter spring 31 isextended between the shutter 21 and the cartridge body 10 to apply anelastic force to the shutter 21 in such a direction as to close theshutter 21.

As shown in FIG. 2, a label plane or concave portion 10 f, on which theuser can note down the contents of the disc 100 stored, is provided onthe bottom of the cartridge body 10 (i.e., the lower shell 11). As alsoshown in FIG. 2, a pair of concave portions 10 c, provided on the right-and left-hand sides of the cartridge body 10, may be used as eitherpull-in notches or positioning recesses when the disc cartridge 301 ispulled in and loaded into a disc drive or when the disc cartridge 301 isstored in a changer. Another concave portion 10 g is provided near oneof the concave portions 10 c. This concave portion 10 g has such a shapeas to prevent the user from inserting this disc cartridge 301 in a wrongdirection. That is to say, this concave portion 10 g is just fitted witha convex portion, provided for the disc drive, only when the disccartridge 301 is inserted in the correct direction. Suppose the usertries to insert the disc cartridge 301 into the disc drive upside downor the wrong way round. In that case, these concave and convex portionsare never fitted with each other, thereby preventing the user frominserting this disc cartridge 301 in the wrong way.

Next, it will be described in further detail with reference to FIGS. 4and 5 how the disc holders 13 and 14 hold the disc 100 thereon. FIG. 4is a cross-sectional view of the disc holder 13 in a state where thedisc 100 has been mounted thereon as shown in FIGS. 1 through 3, whileFIG. 5 is a cross-sectional view of the disc holder 14 in the statewhere the disc 100 has been mounted thereon. FIGS. 3 and 4 are bothtaken in a disc radial direction.

As shown in FIGS. 4 and 5, the disc holders 13 and 14 include slopes 13′and 14′, which are expanded over a portion of the projection area of thedisc 100 (i.e., over the outer periphery of the disc 100), at therespective inner ends thereof. As described above, an elastic force isapplied from the elastic portions 13 d or 14 d to the disc holder 13 or14 in the direction indicated by the arrow 13B or 14B. In thatsituation, the slope 13′ or 14′ contacts with the outer edge 100 c ofthe disc 100, thereby gripping the disc 100 thereon and pressing thedisc 100 in a thickness direction 100 t thereof. As a result, the signalrecording side 100A of the disc 100 is brought into tight contact withthe sheet 11 p. In this manner, the disc 100 is fixed inside thecartridge body 10. In this state, the outer periphery of the signalrecording side 100A of the disc 100 keeps a close contact with the sheet11 p. Thus, no dust will be deposited on the signal recording side 100A.

Next, it will be described in detail with reference to FIGS. 6, 7 and 8how the disc 100 is released from the disc holders 13 and 14.

FIG. 6 is a perspective view illustrating the lower shell 11 of the disccartridge 301 with the upper shell 12 and the disc 100 removedtherefrom. As shown in FIG. 6, the shutter 21 has its L-shaped portion21 s pressed by a shutter opening mechanism (not shown) of the discdrive in the direction indicated by the arrow 21A. As a result, thechucking opening 11 c and the head opening 11 h are now exposed. Also,the cartridge positioning pins 210 of the disc drive are engaged withthe positioning holes 11 w of the cartridge body 10.

FIG. 7 is a cross-sectional view of the disc holder 13 in the stateshown in FIG. 6 and is taken in a disc radial direction. FIG. 8 is aperspective view illustrating the disc holder 14 and the shutter 21 inthe state shown in FIG. 6 to a larger scale.

As shown in FIG. 7, when the cartridge positioning pin 210 of the discdrive is inserted into the positioning hole 11 w of the lower shell 11,the cartridge positioning pin 210 engages with the obliquely runninghole 13 w of the disc holder 13. As a result, the disc holder 13 islifted in the direction indicated by the arrow 13A, and the disc 100 isreleased from the grip of the slope 13′ and is now freely rotatable. Atthis point in time, the rim 13 e at the end of the disc holder 13 stillhangs over a portion of the projection area of the disc 100 (i.e., theouter periphery thereof). Accordingly, even if the disc 100 is releasedin the disc cartridge 301 that has been loaded into a vertically mounteddisc drive, the disc 100 will not drop down from the disc cartridge 301.

On the other hand, when the shutter 21 is opened, a guide rib 21 xprovided on the shutter 21 enters a concave portion 14 w of the discholder 14, thereby raising the bottom of the concave portion 14 w asshown in FIG. 8. As a result, the disc holder 14 is lifted to thedirection indicated by the arrow 14A and the disc 100 is released fromthe grip of the slope 14′ and becomes freely rotatable. At this point intime, the rim 14 e at the end of the disc holder 14 still hangs over aportion of the projection area of the disc 100 (i.e., the outerperiphery thereof). Accordingly, even if the disc 100 is released in thedisc cartridge 301 that has been loaded into a vertically mounted discdrive, the disc 100 will not drop down from the disc cartridge 301.

Also, to remove the disc 100 intentionally, the user must release thedisc 100 from the three disc holders 13 and 14 at the same time.Accordingly, it is possible to prevent the user from removing the disc100 accidentally.

In this preferred embodiment, the end 21 r of the shutter 21, which isopposed to the signal recording side 100A of the disc 100 when theshutter 21 is closed, may be provided with a brush or a dust cleaner asshown in FIG. 2 so that dust is removed from the signal recording side100A of the disc 100 every time the shutter 21 is opened and closed.Optionally, the disc cartridge 301 may also include a locking mechanismfor locking the disc holders 13 and 14 onto the cartridge body 10 whenthe disc 100 is mounted thereon.

Embodiment 2

Hereinafter, a disc cartridge 302 according to a second specificpreferred embodiment of the present invention will be described withreference to FIGS. 9 and 10. Specifically, FIG. 9 is plan viewillustrating an overall configuration for the disc cartridge 302 inwhich the disc 100 is held by disc holders. FIG. 10 is a plan viewillustrating an overall configuration for the disc cartridge 302 inwhich the disc 100 has been released from the disc holders. In FIGS. 9and 10, each member having substantially the same function as thecounterpart of the first preferred embodiment described above isidentified by the same reference numeral and the description thereofwill be omitted herein.

The disc cartridge 302 of the second preferred embodiment is differentfrom the disc cartridge 301 of the first preferred embodiment in thefunction and structure of the disc holders. Specifically, the disccartridge 302 of the second preferred embodiments includes two pairs ofdisc holders 15 and 16, which slide in the direction indicated by thearrow 15A or 15B, as shown in FIG. 9.

Each of the disc holders 15 includes an elastic portion 15 d, whichapplies an elastic force to the disc holder 15 in the directionindicated by the arrow 15B. Just like the disc holders 13 and 14 of thefirst preferred embodiment, a slope 15′ provided at the end of each discholder 15 presses and fixes the disc 100 against the cartridge body 10.

Each of the disc holders 16 includes a shaft 16 c. That is to say, thedisc holder 16 is provided for the cartridge body 10 so as to rotate onits shaft 16 c. Just like the disc holders 13 and 14 of the firstpreferred embodiment, a slope 16′ provided at the end of each discholder 16 presses and fixes the disc 100 against the cartridge body 10.Each of the disc holders 15 further includes a coupling pin 15 p, whichis engaged and interlocked with a groove 16 gof its associated discholder 16.

When the two cartridge positioning pins 210 of the disc drive areengaged with the positioning holes 11 w of the cartridge body 10,respective protrusions 15 s of the disc holders 15 are pushed and liftedby the positioning pins 210 as shown in FIG. 10. As a result, the discholders 15 are moved in the direction indicated by the arrow 15A and thedisc 100 is released from the grip of the slopes 15′. In the meantime,as the disc holders 15 are moved in the direction 15A, the disc holders16 are rotated to the direction indicated by the arrow 16A.Consequently, the disc 100 is also released from the grip of the slopes16′.

Embodiment 3

Hereinafter, a disc cartridge 303 according to a third specificpreferred embodiment of the present invention will be described withreference to FIGS. 11 and 12. Specifically, FIG. 11 is plan viewillustrating an overall configuration for the disc cartridge 303 inwhich the disc 100 is held by disc holders. FIG. 12 is a plan viewillustrating an overall configuration for the disc cartridge 303 inwhich the disc 100 has been released from the disc holders. In FIGS. 11and 12, each member having substantially the same function as thecounterpart of the first preferred embodiment described above isidentified by the same reference numeral and the description thereofwill be omitted herein.

The disc cartridge 303 of the third preferred embodiment is differentfrom the disc cartridge 301 of the first preferred embodiment in thefunction and structure of the disc holders. Specifically, the disccartridge 303 of the third preferred embodiments includes two pairs ofdisc holders 17 and 18, to which an elastic force is applied in thedirections indicated by the arrows 17B and 18B, respectively, as shownin FIG. 11. These disc holders 17 and 18 have been molded together withthe cartridge body 10 so as to form integral parts of the cartridge body10.

Each of the disc holders 17 includes an elastic portion 17 d, whichapplies an elastic force to the disc holder 17 in the directionindicated by the arrow 17B. Just like the disc holders 13 and 14 of thefirst preferred embodiment, a slope 17′ provided at the end of each discholder 17 presses and fixes the disc 100 against the cartridge body 10.

Each of the disc holders 18 also includes an elastic portion 18 d, whichapplies an elastic force to the disc holder 18 in the directionindicated by the arrow 18B. A slope 18′ provided at the end of each discholder 18 also presses and fixes the disc 100 against the cartridge body10.

When this disc cartridge 303 is inserted into a disc drive 200, a pairof disc releasing pins 217, provided for the disc drive 200, pressesprotrusions 17 s of the disc holders 17. As a result, the disc 100 isreleased from the disc holders 17 as shown in FIG. 12. At the same time,another pair of disc releasing pins 218, also provided for the discdrive 200, contacts with the side surfaces 18 s of the disc holders 18.Consequently, the disc 100 is also released from the disc holders 18 asshown in FIG. 12.

Embodiment 4

Hereinafter, a disc cartridge 304 according to a fourth specificpreferred embodiment of the present invention will be described withreference to FIGS. 13 and 14. Specifically, FIG. 13 is plan viewillustrating an overall configuration for the disc cartridge 304 inwhich the disc 100 is held by a disc holder. FIG. 14 is a plan viewillustrating an overall configuration for the disc cartridge 304 inwhich the disc 100 has been released from the disc holder. In FIGS. 13and 14, each member having substantially the same function as thecounterpart of the first preferred embodiment described above isidentified by the same reference numeral and the description thereofwill be omitted herein.

The disc cartridge 304 of the fourth preferred embodiment is differentfrom the disc cartridge 301 of the first preferred embodiment in thefunction and structure of the disc holder. Specifically, the disccartridge 304 includes a ringlike disc holder 19.

As shown in FIG. 13, the disc holder 19 is a ringlike elastic member,which is made of rubber, for example, and can change its shape freely.When no force is externally applied thereto, the disc holder 19 has anellipsoidal planar shape. However, by applying an external forcethereto, the disc holder 19 may be deformed into a substantiallycompletely round shape. In that case, the inside diameter of the discholder 19 is greater than the diameter of the disc 100.

As shown in FIG. 13, the ellipsoidal disc holder 19 is in contact withthe disc 100 at multiple points, thereby fixing the disc 100 onto thecartridge body 10. However, when this disc cartridge 304 is insertedinto a disc drive 200, convex portions 219, provided for the disc drive200, press the major axis portion of the ellipsoidal disc holder 19,thereby deforming the disc holder 19 as shown in FIG. 14. As a result,the disc holder 19 is deformed into an approximately completely roundshape and is no longer in contact with the disc 100. That is to say, thedisc 100 is released from the disc holder 19.

To release the disc 100 from the disc holder 19, the force that deformsthe disc holder 19 may also be applied from the convex portion of thedisc drive 200, which engages with the concave portion 10 g (see FIG. 2)provided for preventing the user from inserting the disc cartridge inthe wrong direction, to the disc holder 19. Alternatively, that forcemay also be applied from a pair of convex portions of the disc drive200, which engages with the concave portions 10 c (see FIG. 2) providedon the right- and left-hand sides of the disc cartridge 304 for pullingin the disc cartridge 304, to the disc holder 19.

Embodiment 5

Hereinafter, a disc cartridge 305 according to a fifth specificpreferred embodiment of the present invention will be described withreference to FIGS. 15 through 18. FIGS. 15 and 17 are plan viewsillustrating the structure of the disc cartridge 305 of the fifthpreferred embodiment from which the upper shell has been removed.Specifically, FIG. 15 illustrates a state where the shutter 21 coversthe openings 11 h and 11 c, while FIG. 17 illustrates a state where theshutter 21 exposes the openings 11 h and 11 c. FIGS. 16 and 18illustrate states of a disc holder 43 when the shutter 21 is closed andwhen the shutter 21 is opened, respectively.

In FIGS. 15 through 18, each member having substantially the samefunction as the counterpart of the first preferred embodiment describedabove is identified by the same reference numeral.

The disc cartridge 305 of the fifth preferred embodiment ischaracterized in that the disc holding and releasing operations and theopening and closing operations are synchronously performed by discholders 43 and the shutter 21, respectively, by way of a discholder/shutter interlocking member 44.

The disc holder/shutter interlocking member 44 is provided over theinner lower surface 11 u so as to rotate and slide around the chuckingopening 11 c of the lower shell 11 as indicated by the arrow 44A inFIGS. 15 and 17. The disc holder/shutter interlocking member 44 has afan shape, or in the shape of a partially notched ring that has aninside diameter equal to the diameter of the chucking opening 11 c.

The disc holder/shutter interlocking member 44 includes a pin 47 thatextends toward the lower shell 11 (i.e., in the direction going into thepaper of FIGS. 15 and 17). The lower shell 11 and the shutter 21 arerespectively provided with guide grooves 11 m and 21 m that both engagewith the pin 47. Also, multiple protrusions 45, which extend outward andupward (i.e., in the direction coming out of the paper of FIGS. 15 and17), are provided on the outer periphery of the disc holder/shutterinterlocking member 44. Furthermore, the upper surface of the discholder/shutter interlocking member 44 is covered with a nonwoven fabricor a coating to prevent the signal recording side 100A of the disc 100from getting scratched or attracting dust.

A number of disc holders 43 are disposed at predetermined intervals onthe inner lower surface 11 u so as to hold the outer edge of the disc100 thereon when the disc 100 is stored in the disc cartridge 305. Inthe preferred embodiment shown in FIGS. 15 and 17, three disc holders 43are provided. Alternatively, two, four or more disc holders 43 may alsobe provided. In any case, each of those disc holders 43 is secured tothe lower shell 11 so as to rotate on the shaft 43A thereof.

As shown in FIG. 16, each of the disc holders 43 is located at such aposition so as to partially overlap with the outer periphery of the discholder/shutter interlocking member 44. Also, an elastic portion (notshown in FIG. 16) such as the elastic portion 14 d shown in FIG. 5, forexample, applies an elastic force to each disc holder 43 downward (i.e.,toward the lower shell 11). Accordingly, while contacting with the outeredge of the disc 100, the slope 43′ of the disc holder 43 not onlypresses the disc 100 in the direction indicated by the arrow 43B in FIG.16 so that the disc 100 is brought into contact with the discholder/shutter interlocking member 44 but also holds the disc 100thereon.

As shown in FIG. 15, when the disc cartridge 305 including the disc (notshown) is inserted into a disc drive 200 in the direction indicated bythe arrow 1A, a shutter opener/closer (not shown), provided for the discdrive 200, moves the shutter 21 in the direction indicated by the arrow21A, thereby opening the shutter 21. When the shutter 21 starts to movein the direction 21A, a force is also applied in the direction 21A tothe pin 47 of the disc holder/shutter interlocking member 44 that isengaged with the guide groove 21 m of the shutter 21. As a result, thepin 47 is moved along the guide groove 11 m of the lower shell 11, andthe disc holder/shutter interlocking member 44 starts to rotate to thedirection indicated by the arrow 44A around the chucking opening 11 c.The guide groove 11 m preferably extends approximately in the directionin which the shutter 21 is moved so that the disc holder/shutterinterlocking member 44 moves along with the shutter 21.

When the shutter 21 is completely open, the protrusions 45 on the outerperiphery of the disc holder/shutter interlocking member 44 are locatedunder the disc holders 43 as shown in FIG. 17. Then, as shown in FIG.18, the disc holders 43 are pushed up by the protrusions 45 and theslopes 43′ of the disc holders 43 separate themselves from the outeredge of the disc 100. As a result, the force that has been verticallyapplied to the disc 100 in the direction indicated by the arrow 43B isremoved from the disc 100 and the disc 100 is now freely rotatable. Atthis point in time, the rim 43 e at the end of the disc holder 43 stillhangs over a portion of the projection area of the disc 100 (i.e., theouter periphery thereof). Accordingly, even if the disc 100 is releasedin the disc cartridge 305 that has been loaded into a vertically mounteddisc drive, the disc 100 will not drop down from the disc cartridge 305.

In the disc cartridge 305 of the fifth preferred embodiment, the disccan be released even if the disc cartridge 305 is not inserted into thedisc drive 200. Accordingly, if the shutter 21 is opened manually, thedisc holders 43 will release the disc 100 synchronously with themovement of the shutter 21. Thus, the user can remove an unwanted discfrom the cartridge 305 and insert a new disc thereto any time he or shelikes.

Embodiment 6

Hereinafter, a disc cartridge 306 according to a sixth specificpreferred embodiment of the present invention will be described withreference to FIGS. 19 and 20. FIGS. 19 and 20 are plan viewsillustrating the structure of the disc cartridge 306 of the sixthpreferred embodiment from which the upper shell has been removed.Specifically, FIG. 19 illustrates a state where the shutter covers thehead opening 11 h, while FIG. 20 illustrates a state where the shutterexposes the opening 11 h. In FIGS. 19 and 20, each member havingsubstantially the same function as the counterpart of the first or fifthpreferred embodiment described above is identified by the same referencenumeral.

The disc cartridge 306 of the sixth preferred embodiment ischaracterized in that the shutter 46 thereof performs the functions ofthe disc holder/shutter interlocking member 44 and the shutter 21 of thedisc cartridge 305 of the fifth preferred embodiment. The shutter 46 isprovided over the inner lower surface 11 u so as to rotate and slidearound the chucking opening 11 c of the lower shell 11 as indicated bythe arrow 46B in FIGS. 19 and 20. The shutter 46 has a fan shape, or inthe shape of a partially notched ring that has an inside diameter equalto the diameter of the chucking opening 11 c.

The shutter 46 includes a pin 46 p that extends toward the lower shell11 (i.e., in the direction going into the paper of FIGS. 19 and 20). Thelower shell 11 is provided with a guide groove 11 m that engages withthe pin 46 p. When the pin 46 p is located at one end of the guidegroove 11 m, the head opening 11 h is closed up by the shutter 46. Andwhen the pin 46 p is located at the other end of the guide groove 11 m,the head opening 11 h is exposed by the shutter 46. The guide groove 11m is provided along a portion of an arc that is concentric with thechuck opening 11 c. The guide groove 11 m preferably extendsapproximately in the direction 1A in which the disc cartridge 306 isinserted into a disc drive 200 so that the shutter 46 is opened as thedisc cartridge 306 is inserted into the disc drive 200.

Multiple protrusions 46 c, which extend outward and upward (i.e., in thedirection coming out of the paper of FIGS. 19 and 20), are provided onthe outer periphery of the shutter 46. Furthermore, the upper surface ofthe shutter 46 is covered with a nonwoven fabric or a coating to preventthe signal recording side 100A of the disc 100 from getting scratched orattracting dust.

A number of disc holders 43, having a structure similar to that of thedisc holders of the fifth preferred embodiment, are disposed atpredetermined intervals on the inner lower surface 11 u. The discholders 43 and the protrusions 46 c of the shutter 46 together hold orrelease the disc synchronously with the movement of the shutter 46 asalready described for the fifth preferred embodiment.

When the disc cartridge 306 of the sixth preferred embodiment isinserted into the disc drive 200 in the direction indicated by the arrow1A in FIG. 19, the pin 46 p of the shutter 46 will soon contact with acontact member 201 provided for the disc drive 200. And when the disccartridge 306 is inserted deeper into the disc drive 200, the pin 46 pis pressed by the contact member 201 to start to move along the guidegroove 11 m. Then, the shutter 46 starts to rotate around the chuckingopening 11 c of the lower shell 11 to the direction indicated by thearrow 46B in FIG. 19. As the shutter 46 rotates to that direction, thehead opening 11 h is opened little by little.

As shown in FIG. 20, when the disc cartridge 306 has been fully insertedinto the disc drive 200, the pin 46 p will reach the other end of theguide groove 11 m. As a result, the head opening 11 h is completelyexposed. At this point in time, as already described for the fifthpreferred embodiment, the protrusions 46 c on the outer periphery of theshutter 46 are located under the disc holders 43 as shown in FIG. 20.Then, the disc holders 43 are pushed up by the protrusions 46 c towardthe upper shell 12 (i.e., in the direction coming out of the paper ofFIG. 20). As a result, the disc 100 that has been held by the discholders 43 is released and now freely rotatable.

The disc cartridge 306 of the sixth preferred embodiment needs no discholder/shutter interlocking member. Thus, compared to the disc cartridge305 of the fifth preferred embodiment, the disc cartridge 306 can bethinner. Also, if the pin 46 p is moved manually along the guide groove11 m, the shutter 46 can be opened and the disc can be released andremoved from the disc holders 43.

In the sixth preferred embodiment described above, the shutter 46 isrotated clockwise as viewed from over the upper shell of the cartridge306. However, the shutter 406 may also be rotated counterclockwise ifthe guide groove 11 m is formed at a different position.

Embodiment 7

Hereinafter, a disc cartridge 307 according to a seventh specificpreferred embodiment of the present invention will be described withreference to FIGS. 21 and 22. FIGS. 21 and 22 are plan viewsillustrating the structure of the disc cartridge 307 of the seventhpreferred embodiment from which the upper shell has been removed.Specifically, FIG. 21 illustrates a state where the shutter covers thehead opening 11 h, while FIG. 22 illustrates a state where the shutterexposes the head opening 11 h. In FIGS. 21 and 22, each member havingsubstantially the same function as the counterpart of the third or sixthpreferred embodiment described above is identified by the same referencenumeral.

The disc cartridge 307 of the seventh preferred embodiment is differentfrom the disc cartridge 306 of the sixth preferred embodiment in thestructure of the disc holders. Specifically, as shown in FIGS. 21 and22, the disc cartridge 307 includes a plurality of disc holders 17. Justlike the disc holders of the third preferred embodiment described above,each of these disc holders 17 also includes an elastic portion 17 d.While the shutter 46 is going to be closed, the elastic portions 17 dapply an elastic force to the disc 100 mounted, thereby holding andpressing the disc 100 toward the center thereof as indicated by thearrows 17R in FIG. 21. In this preferred embodiment, the disc holders 17form integral parts of the lower shell 11. Alternatively, the discholders 17 may also be formed separately from the lower shell 11.

When taken in the disc radial direction, each of these disc holders 17also has a slope that expands over a portion of the projection area ofthe disc (i.e., the outer periphery of the disc 100) just like the discholder 43 shown in FIG. 18. Accordingly, if the disc 100 gets held bythe disc holders 17 so as to have its outer edge contact with therespective slopes of the disc holders 17, then the disc 100 is pressedagainst the shutter 46.

The shutter 46 includes a plurality of protrusions 46 c on the outerperiphery thereof. In this preferred embodiment, the protrusions 46 cprotrude outward. Also, the protrusions 46 c are located at suchpositions on the outer periphery of the shutter 46 as to contact withthe elastic portions 17 d of the disc holders 17 when the shutter 46 isopened as shown in FIG. 22.

As shown in FIG. 22, when the shutter 46 is opened, the protrusions 46 cdominate the inwardly applied elastic force of the elastic portions 17d, thereby pushing the elastic portions 17 d outward as indicated by thearrows 17 s. As a result, the disc 100 is released. However, each of thedisc holders 17 also includes a rim 17 e at the end thereof. Even afterthe disc 100 has been released, the rim 17 e still hangs over a portionof the projection area of the disc 100. Accordingly, even if the disc100 is released in the disc cartridge 307 that has been loaded into avertically mounted disc drive 200, the disc 100 will not drop down fromthe disc cartridge 307.

The disc cartridge 307 of the seventh preferred embodiment achieves allthe effects of the sixth preferred embodiment described above. Inaddition, according to this seventh preferred embodiment, the discholders 17 may form integral parts of the lower shell 11. Then, the disccartridge can have a simplified structure and can be formed at a lowmanufacturing cost.

Embodiment 8

Hereinafter, a disc cartridge 308 according to an eighth specificpreferred embodiment of the present invention will be described withreference to the accompanying drawings.

First, the structure of the disc cartridge 308 will be outlined withreference to FIGS. 23 and 24. As in the first preferred embodimentdescribed above, the disc 100 shown in FIGS. 23 and 24 also includesfirst and second sides. The first side of the disc, on which its label,for example, is normally printed, is illustrated in FIG. 23, while thesecond side thereof, i.e., the signal recording side 100A, isillustrated as the backside in FIG. 24.

As shown in FIGS. 23 and 24, the disc cartridge 308 includes a lowershell 11, an upper shell 12, a pair of shutters 21 and 22 and discstoppers 23.

As shown in FIG. 24, the lower shell 11 includes a chucking opening 11 cand a head opening 11 h. The chucking opening 11 c allows a chuckingmember (e.g., a spindle motor for rotating the disc 100) to enter thedisc cartridge 308 externally. The head opening 11 h allows a head,which reads and/or writes a signal from/on the signal recording side100A of the disc 100, to enter the disc cartridge 308 and access atarget location on the disc 100. The lower shell 11 faces the signalrecording side 100A of the disc 100. Also, the head opening 11 h reachesa side surface of the lower shell 11.

The upper shell 12 includes a circular disc window 12 w, through whichthe disc 100 can be introduced and removed into/from the disc cartridge308 and which expands over the entire projection area of the disc 100 toexpose the upper side of the disc 100. The upper and lower shells 12 and11 are adhered or welded together at their outer periphery, therebyforming a cartridge body 10.

A disc storage portion 10 d for storing the disc 100 therein is definedby an inner lower surface 11 u and an inner side surface 12 i of thecartridge body 10. The inner lower surface 11 u is opposed to the signalrecording side 100A of the disc 100, while the inner side surface 12 ihas a substantially cylindrical shape and defines the disc window 12 winside. That is to say, the inner lower surface 11 u is the bottom ofthe disc storage portion 10 d.

In the disc storage portion 10 d, a gap, which is wide enough to allowthe disc 100 to rotate freely, is provided between the inner sidesurface 12 i and the outer periphery of the disc 100. Also, the innerside surface 12 i is so high that the entire of the disc 100 is storedwithin the disc storage portion 10 d while the disc 100 is rotated. Thetop of the disc storage portion 10 d is the disc window 12 w so that thedisc 100 stored in the disc storage portion 10 d has one of its sidesexposed inside the disc window 12 w.

Two removable disc stoppers 23 are provided for the upper shell 12 so asto partially protrude into the disc window 12 w as shown in FIGS. 23 and24. A third disc stopper 12 s is further provided for the upper shell 12so as to protrude into the disc window 12 w. But the third disc stopper12 s forms an integral part of the upper shell 12. These three discstoppers 23 and 12 s are arranged substantially at regular intervalsaround the circumference of the disc window 12 w for the purpose ofpreventing the disc 100 from dropping down from the disc window 12 wduring the time the shutters 21 and 22 are opened and during the timethe shutters 21 and 22 are closed. These disc stoppers 23 and 12 s areeffective particularly when this disc cartridge 308 is loaded into avertically mounted disc drive.

The shutters 21 and 22 are disposed between the signal recording side100A of the disc 100 and the inner lower surface 11 u of the cartridgebody 10. The shutters 21 and 22 include shaft holes 21 u and 22 u,respectively. These shaft holes 21 u and 22 u are engaged in a freelyrotatable state with shafts 11 s, which are located outside of the discstorage portion 10 d of the cartridge body 10 and on a deep side of thecartridge body 10 opposite to the head opening 11 h thereof. Thus, theshutters 21 and 22 rotate on the shafts 11 s in such a manner as tocover or expose the chucking and head openings 11 c and 11 h.

A cam 21 c and a follower 22 c are provided near the shaft holes 21 uand 22 u of the shutters 21 and 22, respectively. The cam 21 c and thefollower 22 c have mutually engaging shapes and together make up aninterlocking mechanism 20 c for opening and closing the shutters 21 and22 while interlocking them with each other.

The respective upper surfaces of the shutters 21 and 22, which areopposed to the signal recording side 100A of the disc 100, are coveredwith protective layers 21 p and 22 p for the purpose of preventing thesignal recording side 100A of the disc 100 from getting scratched orattracting dust.

The protective layers 21 p and 22 p may be appropriately selected fromthe group consisting of anti-scratching nonwoven fabric, dustproofnonwoven fabric, anti-scratching coating and dustproof coating. In thispreferred embodiment, sheets of a dustproof nonwoven fabric are adheredor ultrasonic welded as the protective layers 21 p and 22 p to theshutters 21 and 22, respectively.

Shutter springs 31 and 32 are provided outside of the disc storageportion 10 d for the shutters 21 and 22, respectively. These springs 31and 32 apply an elastic force to the shutters 21 and 22 in such adirection as to close the shutters 21 and 22. Optionally, an elasticforce may also be applied from any other type of elastic members to theshutters 21 and 22 in that direction.

In the disc cartridge 308 shown in FIG. 24, the shutters 21 and 22 eachinclude two disc holders 21 a, 21 b and 22 a, 22 b at both ends thereof.Each of these disc holders 21 a, 21 b, 22 a and 22 b has a downwardlytapered cross-sectional shape (or slope) to grip the outer edge of thedisc 100 while the shutters 21 and 22 are closed. The structure andoperation of the disc holders 21 a, 21 b, 22 a and 22 b will bedescribed in further detail later.

As shown in FIG. 23, the upper surface of the cartridge body 10 (or theupper shell 12) has a label plane 10 f, on which the user can note downthe contents of the disc 100 stored, and embossed arrow marks (orconcave portions) 10 a that indicate the direction (the arrow 1A) inwhich this disc cartridge 308 should be inserted into a disc drive. Thecartridge body 10 further includes two concave portions 10 c on two ofits side surfaces that are parallel to the direction 1A in which thedisc cartridge 308 is inserted. These concave portions 10 c may be usedas either pull-in notches or positioning recesses when the disccartridge 308 is pulled in and loaded into a disc drive or when the disccartridge 308 is stored in a disc changer.

FIG. 25 is a perspective view illustrating the disc cartridge 308 withthe upper shell 12 and the disc 100 removed to show a state where theshutters 21 and 22 cover the chucking and head openings 11 c and 11 h.In FIG. 25, the disc holders 21 a, 21 b, 22 a and 22 b of the shutters21 and 22 are located at such positions as to grip the outer edge of thedisc 100 (not shown in FIG. 25).

FIG. 26 is a perspective view illustrating the disc cartridge 308 withthe upper shell 12 and the disc 100 removed to show a state where theshutters 21 and 22 expose the chucking and head openings 11 c and 11 h.As a result of the rotation of the shutters 21 and 22 on their shaftholes 21 u and 22 u, respectively, the chucking and head openings 11 cand 11 h are now exposed. Also, as the shutters 21 and 22 have rotated,the disc holders 21 a, 21 b, 22 a and 22 b have also rotated on theshaft holes 21 u and 22 u. Consequently, the disc holders 21 a, 21 b, 22a and 22 b are now separated from the outer edge of the disc 100 (notshown in FIG. 26).

FIG. 27 is a perspective view illustrating the disc cartridge 308, onwhich the disc 100 has not been mounted yet, to show a state where theshutters 21 and 22 cover the chucking and head openings 11 c and 11 h.As shown in FIG. 27, the disc holders 21 a, 21 b, 22 a and 22 b protrudeinto the disc storage portion 10 d. Thus, when the disc 100 is stored inthis disc cartridge 308, the disc 100 is held by these disc holders 21a, 21 b, 22 a and 22 b. On the other hand, FIG. 28 is a perspective viewillustrating the disc cartridge 308, on which the disc 100 has not beenmounted yet, to show a state where the shutters 21 and 22 expose thechucking and head openings 11 c and 11 h. As shown in FIG. 28, while theshutters 21 and 22 are opened, the disc holders 21 a, 21 b, 22 a and 22b are stored outside of the disc storage portion 10 d of the cartridgebody 10.

Next, the structure and the operation of the shutters 21 and 22 will bedescribed in further detail with reference to FIGS. 29, 30 and 31. FIG.29 is a partial cross-sectional view of the disc cartridge 308, which isviewed along a plane that passes the center of the disc 100. As shown inFIG. 29, the inner side surface 12 i of the cartridge body 10 isprovided with a notched portion 10 w so as not to interfere with theopening and closing operations of the shutters 21 and 22. Also, thecartridge body 10 further includes shutter storage 10 s for storing aportion of the shutters 21 and 22 being opened. Furthermore, at leastthe edges 21 f and 22 f of the shutters 21 and 22, which are buttedagainst each other over the chucking and head openings 11 c and 11 hwhile the shutters 21 and 22 are closed, overlap. with each othervertically (i.e., in the thickness direction of the disc 100) as shownin FIG. 29.

On the other hand, as shown in FIG. 30, each of the disc holders 21 a,21 b, 22 a and 22 b includes a slope 21 a′, 21 b′, 22 a′ or 22 b′, whichhangs over the projection area of the disc 100 and overlaps with theouter edge of the disc 100. That is to say, the slope 21 a′, 21 b′, 22a′ or 22 b′ has a downwardly tapered cross section and leans toward thedisc 100 as shown in FIG. 30. While the chucking and head openings 11 cand 11 h are covered with the shutters 21 and 22, the slopes 21 a′, 21b′, 22 a′ and 22 b′ are allowed to contact with the outer edge 100 c ofthe disc 100, thereby gripping the disc 100 thereon and pressing thedisc 100 in the thickness direction 100 t. As a result, the sheets 21 pand 22 p of the shutters 21 and 22 contact with the signal recordingside 100A of the disc 100 and the disc 100 is fixed in the cartridgebody 10. In such a state, the signal recording side 100A of the disc 100is in close contact with the sheets 21 p and 22 p. Thus, no dust will bedeposited on the signal recording side 100A.

Also, if the exposed side of the disc 100 is rotated manually or if theshutters 21 and 22 are opened or closed intentionally, then dust, fingermarks or any other dirt that has adhered onto the signal recording side100A of the disc 100 may be wiped away.

Furthermore, as shown in FIG. 31, the shutter 21 includes a shutteropener/closer 21 t, an elastic portion 21 v and a locking protrusion 21k. These portions 21 t, 21 v and 21 k form integral parts of the shutter21. Specifically, the shutter opener/closer 21 t is for use to open andclose the shutter 21 externally. The locking protrusion 21 k isconnected to the shutter 21 by way of the elastic portion 21 v. Whilethe shutter 21 covers the chucking and head openings 11 c and 11 h, thelocking protrusion 21 k, to which an elastic force is being applied fromthe elastic portion 21 v, engages with a locking hole 10 k of thecartridge body 10, thereby preventing the shutter 21 from rotating andfixing the shutter 21 to the cartridge body 10 as shown in FIG. 31. Whenthe shutter 21 is fixed, the other shutter 22, which is interlocked withthe former shutter 21 via the interlocking mechanism 20 c, is alsofixed.

Accordingly, only by getting the locking protrusion 21 k pressedexternally by a protrusion, for example, in the direction indicated bythe arrow 20A and disengaged from the locking hole 10 k while pressingthe opener/closer 21 t in the direction indicated by the arrow 20B atthe same time, the shutters 21 and 22 can be rotated to expose thechucking and head openings 11 c and 11 h and the disc 100 can bereleased from the disc holders 21 a, 21 b, 22 a and 22 b. Thus, it ispossible to prevent the user from removing the disc 100 accidentally.

Next, the structure and operation of the disc stoppers 23 will bedescribed in further detail with reference to FIGS. 24 and 32. FIG. 32is a perspective view illustrating the removable disc stopper 23 upsidedown. The convex portions 23 a, 23 b and 23 c of the disc stopper 23 arerespectively engaged with concave portions 12 a, 12 b and 12 c providedfor the upper shell 12 near the disc window 12 w thereof as shown inFIG. 24. Thus, if these convex portions 23 a, 23 b and 23 c aredisengaged from the concave portions 12 a, 12 b and 12 c, the discstopper 23 can be removed from the upper shell 12.

Next, a mechanism for preventing the user from inserting this disccartridge 308 into a disc drive in the wrong way will be described withreference to FIG. 33. FIG. 33 is a front view illustrating the insertionside of the disc cartridge 308 shown in FIG. 23 as viewed in thedirection 1B (see FIG. 23). As shown in FIG. 33, the cartridge body 10includes a concave portion 10 g on one side surface thereof and isasymmetric in the direction 1A in which the disc cartridge 308 isinserted into the disc drive (see FIG. 23). The concave portion 10 g isnot located at the center of thickness of the cartridge body 10.

By providing such a concave portion 10 g for the disc cartridge 308,only when its associated convex portion, provided for the disc drive, isfitted with this concave portion 10 g, the disc cartridge 308 can beinserted into the disc drive correctly and the disc drive can operatenormally.

Stated otherwise, even if the user tries to insert the disc cartridge308 into the disc drive upside down by mistake, he or she cannot insertthe cartridge 308 into the disc drive. This is because the associatedconvex portion of the disc drive interferes with the other side surfaceof the disc cartridge 308 with no concave portion 10 g. Also, even ifthe user tries to insert the disc cartridge 308 into the disc driveupside down and in the wrong way by mistake, he or she cannot insert thecartridge 308 into the disc drive, either. This is because the convexportion of the disc drive also interferes with the non-recessed portionof the side surface with the concave portion 10 g. Thus, it is possibleto prevent the user from inserting the disc cartridge 308 erroneously.

The disc cartridge 308 of the eighth preferred embodiment describedabove may be modified in various manners.

For example, the thickness of the cartridge body 10 may be furtherreduced to such an extent that the disc stoppers 23 will not protrudefrom the upper surface 12 f of the upper shell 12 (see FIG. 24) whilethe shutters 21 and 22 are closed. In that case, while the shutters 21and 22 are going to be opened, the disc holders 21 a and 22 a may pushthe respective convex portions 23 a of the disc stoppers 23 upward fromunder the disc stoppers 23, thereby protruding the disc stoppers 23 fromthe upper surface 12 f of the upper shell 12. According to such astructure, a sufficiently broad space can be allowed the disc 100 torotate inside the disc storage portion 10 d and yet the disc cartridge308 can have its thickness further reduced.

Also, the disc stoppers 23 may form integral parts of the cartridge body10. In that case, the disc stoppers 23 should be able to be bent almostperpendicularly so that the disc 100 mounted can be removed.

Furthermore, the shutter springs 31 and 32 may apply an elastic force insuch a direction as to open the shutters 21 and 22. If the shutters 21and 22 can operate almost completely synchronously by way of theinterlocking mechanism, one of the shutter springs 31 and 32 may beomitted.

In the preferred embodiment described above, the locking protrusion 21 kforms an integral part of the shutter 21. Alternatively, a lockinglever, including a locking protrusion and a convex portion at the endthereof, may be connected to the cartridge body 10 via an elasticportion, and an associated concave portion may be provided for theshutter so that the convex and concave portions engage with each other.In that case, by pressing the locking protrusion through a locking holeof the cartridge body, these convex and concave portions may bedisengaged from each other so as to allow the shutters to rotate freely.Optionally, in that alternative preferred embodiment, the locking lever,as well as the shutter springs (i.e., elastic members), may be resinsprings that form integral parts of the cartridge body 10.

Embodiment 9

Hereinafter, a disc cartridge 309 according to a ninth specificpreferred embodiment of the present invention will be described withreference to the accompanying drawings.

As shown in FIGS. 34 and 35, the disc cartridge 309 includes a lowershell 41, an upper shell 42, disc stoppers 42 a, 42 b, 42 c and 42 d,and a pair of shutters 51 and 52.

As shown in FIG. 35, the lower shell 41 includes a chucking opening 41 cand a head opening 41 h. The chucking opening 41 c allows a chuckingmember (e.g., a spindle motor for rotating the disc 100) to enter thedisc cartridge 309 externally. The head opening 41 h allows a head,which reads and/or writes a signal from/on the signal recording side100A of the disc 100, to enter the disc cartridge 309 and access atarget location on the disc 100. The lower shell 41 faces the signalrecording side 100A of the disc 100. Also, the head opening 41 h reachesone side surface of the lower shell 41.

The upper shell 42 includes a circular disc window 42 w, through whichthe disc 100 can be introduced and removed into/from the disc cartridge309 and which expands over the entire projection area of the disc 100 toexpose the upper side of the disc 100. The upper and lower shells 42 and41 are adhered or welded together at their outer periphery, therebyforming a cartridge body 40.

A disc storage portion 40 d for storing the disc 100 therein is definedby a first inner surface 41 u and a second inner surface 42i of thecartridge body 40. The first inner surface 41 u is opposed to the signalrecording side 100A of the disc 100, while the second inner surface 42 ihas a substantially cylindrical shape and defines the disc window 42 winside. That is to say, the first inner surface 41 u is the bottom ofthe disc storage portion 40 d.

In the disc storage portion 40 d, a gap, which is wide enough to allowthe disc 100 to rotate freely, is provided between the second innersurface 42 i and the outer periphery of the disc 100. Also, the top ofthe disc storage portion 40 d is the disc window 42 w so that the disc100 stored in the disc storage portion 40 d has one of its sides exposedinside the disc window 42 w.

The disc stoppers 42 a, 42 b, 42 c and 42 d form integral parts of theupper shell 42 so as to partially protrude into the disc window 42 w.Each of these disc stoppers 42 a, 42 b, 42 c and 42 d is separated fromthe upper shell 42 via a slit. These disc stoppers 42 a, 42 b, 42 c and42 d are used to prevent the disc 100 from dropping down from the discwindow 42 w. The disc stoppers 42 a, 42 b, 42 c and 42 d are effectiveparticularly when this disc cartridge 309 is loaded into a verticallymounted disc drive. Optionally, these disc stoppers 42 a, 42 b, 42 c and42 d may be integrated with the upper shell 42 by way of elasticmembers.

The shutters 51 and 52 are disposed between the signal recording side100A of the disc 100 and the first inner surface 41 u of the cartridgebody 40. The shutters 51 and 52 include shaft holes 51 u and 52 u,respectively. These shaft holes 51 u and 52 u are engaged in a freelyrotatable state with shafts 41 s, which are located outside of the discstorage portion 40 d of the cartridge body 40 and on a deep side of thecartridge body 40 opposite to the head opening 41 h thereof. Thus, theshutters 51 and 52 rotate on the shafts 41 s in such a manner as tocover or expose the chucking and head openings 41 c and 41 h.

A cam 51 c and a follower 52 c are provided near the shaft holes 51 uand 52 u of the shutters 51 and 52, respectively. The cam 51 c and thefollower 52 c have mutually engaging shapes and together make up aninterlocking mechanism 50 c for opening and closing the shutters 51 and52 while interlocking them with each other.

The respective upper surfaces of the shutters 51 and 52, which areopposed to the signal recording side 100A of the disc 100, are coveredwith protective layers 51 p and 52 p for the purpose of preventing thesignal recording side 100A of the disc 100 from getting scratched orattracting dust.

The protective layers 51 p and 52 p may be appropriately selected fromthe group consisting of anti-scratching nonwoven fabric, dustproofnonwoven fabric, anti-scratching coating and dustproof coating. In thispreferred embodiment, sheets of a dustproof nonwoven fabric are adheredor ultrasonic welded as the protective layers 51 p and 52 p to theshutters 51 and 52, respectively.

Shutter springs 61 and 62 are provided outside of the disc storageportion 40 d for the shutters 51 and 52, respectively. These springs 61and 62 apply an elastic force to the shutters 51 and 52 in such adirection as to close the shutters 51 and 52. Alternatively, the shuttersprings 61 and 62 may apply an elastic force to the shutters 51 and 52in such a direction as to open the shutters 51 and 52. Also, if theshutters 51 and 52 can operate almost completely synchronously by way ofthe interlocking mechanism, one of the shutter springs 61 and 62 may beomitted.

As in the eighth preferred embodiment described above, the shutters 51and 52 each include two disc holders 51 a, 51 b and 52 a, 52 b at bothends thereof as shown in FIG. 35. Furthermore, as will be described indetail later, convex portions 51 e and 52 e are formed on the shutters51 and 52, respectively, so as to be located under the center hole ofthe disc 100 while the shutters 51 and 52 are closed.

As shown in FIG. 34, the upper surface of the cartridge body 40 (or theupper shell 42) has embossed arrow marks (or concave portions) 40 a thatindicate the direction (the arrow 1A) in which this disc cartridge 309should be inserted into a disc drive. The cartridge body 40 furtherincludes two concave portions 40 c on two of its side surfaces that areparallel to the direction 1A in which the disc cartridge 309 is insertedinto the disc drive. These concave portions 40 c may be used as eitherpull-in notches or positioning recesses when the disc cartridge 309 ispulled in and loaded into a disc drive or when the disc cartridge 309 isstored in a disc changer. Optionally, only one of the side surfaces ofthe disc cartridge 309 may include the concave portion 40 c. In thatcase, the concave portion 40 c can contribute to preventing the userfrom inserting or loading this disc cartridge 309 into the disc driveupside down by mistake. The upper surface of the cartridge body 40further includes a grip 40 e that allows the user to grip this disccartridge 309. This grip 40 e has an antislip embossed shape.

FIG. 36 is a perspective view illustrating the disc cartridge 309, inwhich no disc 100 has been stored yet, to show a state where theshutters 51 and 52 cover the chucking and head openings 41 c and 41 h.FIG. 37 is a perspective view illustrating the disc cartridge 309, inwhich no disc 100 has been stored yet, to show a state where theshutters 51 and 52 expose the chucking and head openings 41 c and 41 h.

Hereinafter, the structure and the operation of the shutters 51 and 52will be described in further detail. As shown in FIGS. 34 and 35, thedisc holders 51 a, 51 b, 52 a and 52 b of the shutters 51 and 52 alsohave such a cross-sectional shape as including a slope that hangs overthe projection area of the disc 100 and overlaps with the outer edge ofthe disc 100 as in the eighth preferred embodiment. That is to say, theslope is downwardly tapered and leans toward the disc 100. Thus, theeffects of the eighth preferred embodiment described above are alsoachieved by this ninth preferred embodiment.

Also, the shutter 52 includes an opener/closer 52t for use to open andclose the shutter 52 externally, while the shutter 51 includes anelastic portion 51 v and a locking protrusion 51 k as integral partsthereof. The locking protrusion 51 k is connected to the shutter 51 byway of the elastic portion 51 v as shown in FIG. 35. Thus, while thechucking and head openings 41 c and 41 h are covered with the shutters51 and 52, the locking protrusion 51 k, to which an elastic force isapplied from the elastic portion 51 v, engages with a locking hole 40 kof the cartridge body 40 (or the lower shell 41), thereby fixing theshutter 51 in a non-rotatable state to the cartridge body 40. When theshutter 51 is fixed in this way, the other shutter 52, which isinterlocked with the shutter 51 via the interlocking mechanism 50 c, isalso fixed.

Accordingly, only by getting the locking protrusion 51 k pressedexternally by a protrusion, for example, in the direction indicated bythe arrow 50A and disengaged from the locking hole 40 k while pressingthe opener/closer 52 t in the direction indicated by the arrow 50B atthe same time as shown in FIG. 36, the shutters 51 and 52 can be rotatedto expose the chucking and head openings 41 c and 41 h and the disc 100can be released from the disc holders 51 a, 51 b, 52 a and 52 b. Thus,it is possible to prevent the user from removing the disc 100accidentally.

Unlike the eighth preferred embodiment described above, the lockingprotrusion 51 k and the opener/closer 52 t are provided in thispreferred embodiment for the two different shutters 51 and 52. Such astructure is particularly effective for a disc cartridge for a disc of asmall size. This is because a disc cartridge for a disc of a small sizeand the shutters thereof should have relatively small sizes and it isnormally difficult to provide the locking protrusion and opener/closerfor a single shutter out of design considerations. Also, even when asingle shutter can include both the locking protrusion and theopener/closer, a very narrow gap would be allowed between a shutteropening/closing mechanism and an unlocking mechanism on the disc driveside or these two mechanisms need to be formed within a very limitedspace, thus making it hard to design the disc drive as intended.

In the preferred embodiment described above, the locking protrusion 51 kforms an integral part of the shutter 51. Alternatively, a lockinglever, including a locking protrusion and a convex portion at the endthereof, may be connected to the cartridge body 40 by way of an elasticportion, and an associated concave portion may be provided for theshutter so that the convex and concave portions engage with each other.In that case, by pressing the locking protrusion through a locking holeof the cartridge body, these convex and concave portions may bedisengaged from each other so as to allow the shutters to rotate freely.Optionally, in that alternative preferred embodiment, the locking lever,as well as the shutter springs (i.e., elastic members), may be resinsprings that form integral parts of the cartridge body 40.

Next, it will be described how the convex portions 51 e and 52 e on theshutters 51 and 52 work. FIG. 38 is a partial cross-sectional view ofthe disc cartridge 309, which is viewed along a plane that passes thecenter of the disc 100. As shown in FIG. 38, while the shutters 51 and52 are closed, the convex portions 51 e and 52 e protrude into thecenter hole 100 h of the disc 100 and the disc 100 is now in contactwith the shutters 51 and 52.

As shown in FIG. 39, while the shutters 51 and 52 are going to beopened, the convex portions 51 e and 52 e slide from inside the centerhole 100 h into under the lower side of the disc 100, thereby liftingthe disc 100 up from the shutters 51 and 52. In this manner, while theshutters 51 and 52 are going to be opened or closed, the signalrecording side 100A of the disc 100 will not get scratched by theshutters 51 and 52. Also, it is inside the signal recording area of thesignal recording side 100A that the convex portions 51 e and 52 e movealong with the shutters 51 and 52 being opened or closed. Accordingly,the convex portions 51 e and 52 e will not contact with, or scratch, thesignal recording area.

Next, the structure and operation of the disc stoppers will be describedwith reference to FIGS. 40 and 41. FIG. 40 is a partial cross-sectionalview illustrating a portion of the disc cartridge 309 around the discouter periphery, and is viewed along a plane that passes the center ofthe disc 100. As shown in FIG. 40, a convex portion 42 a′, 42 b′, 42 c′or 42 d′ has been formed on the bottom of the disc stopper 42 a, 42 b,42 c or 42 d. While the shutters 51 and 52 are closed, the disc stopper42 a, 42 b, 42 c or 42 d is substantially parallel to the surface of thedisc 100 and falls within the thickness of the cartridge 309 as shown inFIG. 40. An appearance of the disc cartridge 309 in such a state isillustrated in FIG. 36.

On the other hand, while the shutters 51 and 52 are opened, the slopes52 f, 51 f, 51 d and 52 d of the shutters 51 and 52 contact with theconvex portions 42 a′, 42 b′, 42 c′ and or 42 d′, respectively, therebylifting the disc stoppers 42 a, 42 b, 42 c and 42 d to above the disc100 as shown in FIG. 41. An appearance of the disc cartridge 309 in sucha state is illustrated in FIG. 37. By using such a structure,particularly in an interval after the disc cartridge 309 has beenvertically loaded into a disc drive and before the disc 100 is chucked,it is possible to prevent the disc 100 from dropping down from thecartridge 309. In addition, while the disc 100 is being chucked, thedisc 100 can move in a broader space. Furthermore, this structure canalso contribute to further reducing the thickness of the cartridge.

It should be noted that to keep the shutters 51 and 52 temporarilyopened for a while, the slopes 52 f, 51 f, 51 d and 52 d may have convexor concave portions that engage with the convex portions 42 a′, 42 b′,42 c′ and 42 d′.

Embodiment 10

Hereinafter, a disc cartridge 310 according to a tenth specificpreferred embodiment of the present invention will be described withreference to the accompanying drawings. The disc cartridge 310 of thispreferred embodiment is mainly characterized in that disc stoppers areprovided for the shutters.

As shown in FIGS. 42 and 43, the disc cartridge 310 includes a lowershell 71, an upper shell 72, disc stoppers 81 d, 81 f, and 82 d, and apair of shutters 81 and 82.

As shown in FIG. 43, the lower shell 71 includes a chucking opening 71 cand a head opening 71 h. The chucking opening 71 c allows a chuckingmember (e.g., a spindle motor for rotating the disc 100) to enter thedisc cartridge 310 externally. The head opening 71 h allows a head,which reads and/or writes a signal from/on the signal recording side100A of the disc 100, to enter the disc cartridge 310 and access atarget location on the disc 100. The lower shell 71 faces the signalrecording side 100A of the disc 100. Also, the head opening 71 h reachesone side surface of the lower shell 71.

The upper shell 72 includes a circular disc window 72 w, through whichthe disc 100 can be introduced and removed into/from the disc cartridge310 and which expands over the entire projection area of the disc 100 toexpose the upper side of the disc 100. The upper and lower shells 72 and71 are adhered or welded together at their outer periphery, therebyforming a cartridge body 70.

A disc storage portion 70 d for storing the disc 100 therein is definedby a first inner surface 71 u and a second inner surface 72 i of thecartridge body 70. The first inner surface 71 u is opposed to the signalrecording side 100A of the disc 100, while the second inner surface 72 ihas a substantially cylindrical shape and defines the disc window 72 winside. That is to say, the first inner surface 71 u is the bottom ofthe disc storage portion 70 d.

In the disc storage portion 70 d, a gap, which is wide enough to allowthe disc 100 to rotate freely, is provided between the second innersurface 72 i and the outer periphery of the disc 100. Also, the top ofthe disc storage portion 70 d is the disc window 72 w so that the disc100 stored in the disc storage portion 70 d has one of its sides exposedinside the disc window 72 w.

The shutters 81 and 82 are disposed between the signal recording side100A of the disc 100 and the first inner surface 71 u of the cartridgebody 70. The shutters 81 and 82 include shaft holes 81 u and 82 u,respectively. These shaft holes 81 u and 82 u are engaged in a freelyrotatable state with shafts 71 s, which are located outside of the discstorage portion 70 d of the cartridge body 70 and on a deep side of thecartridge body 70 opposite to the head opening 71 h thereof. Thus, theshutters 81 and 82 rotate on the shafts 71 s in such a manner as tocover or expose the chucking and head openings 71 c and 71 h.

A cam 81 c and a follower 82 c are provided near the shaft holes 81 uand 82 u of the shutters 81 and 82, respectively. The cam 81 c and thefollower 82 c have mutually engaging shapes and together make up aninterlocking mechanism 80 c for opening and closing the shutters 81 and82 while interlocking them with each other.

The respective upper surfaces of the shutters 81 and 82, which areopposed to the signal recording side 100A of the disc 100, are coveredwith protective layers 81 p and 82 p for the purpose of preventing thesignal recording side 100A of the disc 100 from getting scratched orattracting dust.

The protective layers 81 p and 82 p may be appropriately selected fromthe group consisting of anti-scratching nonwoven fabric, dustproofnonwoven fabric, anti-scratching coating and dustproof coating. In thispreferred embodiment, sheets of a dustproof nonwoven fabric are adheredor ultrasonic welded as the protective layers 81 p and 82 p to theshutters 81 and 82, respectively.

Shutter springs 91 and 92 are provided outside of the disc storageportion 70 d for the shutters 81 and 82, respectively. These springs 91and 92 apply an elastic force to the shutters 81 and 82 in such adirection as to close the shutters 81 and 82. Alternatively, the shuttersprings 91 and 92 may apply an elastic force to the shutters 81 and 82in such a direction as to open the shutters 81 and 82. Also, if theshutters 81 and 82 can operate almost completely synchronously by way ofthe interlocking mechanism 80 c, one of the shutter springs 91 and 92may be omitted.

As in the eighth preferred embodiment described above, the shutters 81and 82 each include two disc holders 81 a, 81 b and 82 a, 82 b at bothends thereof as shown in FIG. 43. Convex portions 81 e and 82 e are alsoformed on the shutters 81 and 82, respectively, as in the ninthpreferred embodiment.

Furthermore, as will be described in detail later, the disc stoppers 81f, 81 d and 82 d are provided as integral parts of the shutters 81 and82 near the disc holders 81 a, 81 b and 82 a, respectively.Alternatively, these disc stoppers 81 f, 81 d and 82 d may be integratedwith the shutters 81 and 82 by way of elastic members.

As shown in FIG. 42, the upper surface of the cartridge body 70 (or theupper shell 72) has embossed arrow marks (or concave portions) 70 a thatindicate the direction (the arrow 1A) in which this disc cartridge 310should be inserted into a disc drive. The cartridge body 70 furtherincludes two concave portions 70 c on two of its side surfaces that areparallel to the direction 1A in which the disc cartridge 310 isinserted. These concave portions 70 c may be used as either pull-innotches or positioning recesses when the disc cartridge 310 is pulled inand loaded into a disc drive or when the disc cartridge 310 is stored ina disc changer. Optionally, only one of the side surfaces of the disccartridge 310 may include the concave portion 70 c. In that case, theconcave portion 70 c can contribute to preventing the user frominserting or loading this disc cartridge 310 into the disc drive upsidedown by mistake. The upper surface of the cartridge body 70 furtherincludes a grip 70 e that allows the user to grip this disc cartridge310. This grip 70 e has an antislip embossed shape.

FIG. 44 is a perspective view illustrating the disc cartridge 310, inwhich no disc 100 has been stored yet, to show a state where theshutters 81 and 82 cover the chucking and head openings 71 c and 71 h.FIG. 45 is a perspective view illustrating the disc cartridge 310, inwhich no disc 100 has been stored yet, to show a state where theshutters 81 and 82 expose the chucking and head openings 71 c and 71 h.

Hereinafter, the structure and the operation of the shutters 81 and 82will be described in further detail. As shown in FIGS. 42 and 43, thedisc holders 81 a, 81 b, 82 a and 82 b of the shutters 81 and 82 havesuch a cross-sectional shape as including a slope that hangs over theprojection area of the disc 100 and overlaps with the outer edge of thedisc 100 as in the eighth preferred embodiment. That is to say, theslope is downwardly tapered and leans toward the disc 100. Thus, theeffects of the eighth preferred embodiment described above are alsoachieved by this tenth preferred embodiment.

Also, the shutter 82 includes an opener/closer 82 t for use to open andclose the shutter 82 externally, an elastic portion 82 v and a lockingprotrusion 82 k as integral parts thereof. The locking protrusion 82 kis connected to the shutter 82 by way of the elastic portion 82 v asshown in FIG. 43. Thus, while the chucking and head openings 71 c and 71h are covered with the shutters 81 and 82, the locking protrusion 82 k,to which an elastic force is applied from the elastic portion 82 v,engages with a locking hole 70 k of the cartridge body 70 (or the lowershell 71) as shown in FIG. 44, thereby fixing the shutter 82 in anon-rotatable state to the cartridge body 70. When the shutter 82 isfixed in this way, the other shutter 81, which is interlocked with theshutter 82 via the interlocking mechanism 80 c, is also fixed.

Accordingly, only by getting the locking protrusion 82 k pressedexternally by a protrusion, for example, in the direction indicated bythe arrow 70A and disengaged from the locking hole 70 k while pressingthe opener/closer 82 t in the direction indicated by the arrow 70B atthe same time as shown in FIG. 44, the shutters 81 and 82 can be rotatedto expose the chucking and head openings 71 c and 71 h and the disc 100can be released from the disc holders 81 a, 81 b, 82 a and 82 b. Thus,it is possible to prevent the user from removing the disc 100accidentally.

In the preferred embodiment described above, the locking protrusion 82 kforms an integral part of the shutter 82. Alternatively, a lockinglever, including a locking protrusion and a convex portion at the endthereof, may be connected to the cartridge body 70 by way of an elasticportion, and a concave portion may be provided for the shutter so thatthe convex and concave portions engage with each other. In that case, bypressing the locking protrusion through a locking hole of the cartridgebody, these convex and concave portions may be disengaged from eachother so as to allow the shutters to rotate freely. Optionally, in thatalternative preferred embodiment, the locking lever, as well as theshutter springs (i.e., elastic members), may be resin springs that formintegral parts of the cartridge body 70.

Next, the structure and operation of the disc stoppers 81 f, 81 d and 82d will be described in further detail. While the shutters 81 and 82 areclosed, the disc stoppers 81 f, 81 d and 82 d are substantially parallelto the surface of the disc 100 and do not protrude from the uppersurface of the disc cartridge 310 as shown in FIGS. 46 and 48. Anappearance of the disc cartridge 310 in such a state is illustrated inFIG. 44.

On the other hand, while the shutters 81 and 82 are going to be opened,the disc stoppers 81 f, 81 d and 82 d are guided by a slit 70 s and aslope 72 s of the cartridge body 70 so as to be lifted to above the disc100 as shown in FIGS. 47 and 49. The slit 70 s is formed in the innersidewall of the cartridge body 70 as shown in FIG. 47, while the slope72 s is formed on the inner upper surface of the cartridge body 70 asshown in FIG. 49. Also, the upper shell 72 is provided with notchedportions 72 a, 72 b and 72 c so as not to interfere with the discstoppers 81 f, 81 d and 82 d that have been lifted up. An appearance ofthe disc cartridge 310 in such a state is illustrated in FIG. 45.

While the shutters 81 and 82 are closed, the disc stoppers 81 f, 81 dand 82 d hang over the projection area of the disc 100 and overlap withthe outer periphery of the disc 100. Thus, the disc stoppers 81 f, 81 dand 82 d press the disc 100 against the shutters 81 and 82 in thethickness direction, thereby holding it thereon. Accordingly, the discholders 81 a, 81 b, 82 a and 82 b may be omitted from the shutters 81and 82.

By using such a structure, particularly in an interval after the disccartridge 310 has been vertically loaded into a disc drive and beforethe disc 100 is chucked, it is possible to prevent the disc 100 fromdropping down from the cartridge 310. In addition, while the disc 100 isbeing chucked, the disc 100 can move in a broader space. Furthermore,this structure can also contribute to further reducing the thickness ofthe cartridge body.

Embodiment 11

Hereinafter, a disc cartridge 311 according to an eleventh specificpreferred embodiment of the present invention will be described withreference to the accompanying drawings.

As shown in FIGS. 50 and 51, the disc cartridge 311 includes a lowershell 11, an upper shell 12, a pair of shutters 21 and 22 and discstoppers 23. As shown in FIGS. 52 through 56, the structures andfunctions of all of these members are the same as those alreadydescribed for the eighth preferred embodiment and the detaileddescription thereof will be omitted herein.

Unlike the disc cartridge 308 of the eighth preferred embodimentdescribed above, the shutters 21 and 22 of the disc cartridge 311 of theeleventh preferred embodiment have a hole 20 h as shown in FIGS. 50 and51.

More specifically, while the shutters 21 and 22 of the disc cartridge311 are closed, the shutters 21 and 22 define the hole 20 h just underthe center hole 100 h of the disc 100 as shown in FIG. 50. As can beseen from FIG. 51, the hole 20 h is made up of two notches 21 h and 22 hof the shutters 21 and 22, respectively.

If the disc cartridge 311 is left with the upper side of the disc 100exposed upward as shown in FIG. 50, dust may pass through the centerhole 100 h of the disc 100. Even so, in this structure, the dust shouldpass and go out through the hole 20 h of the shutters 21 and 22 withoutremaining in the disc cartridge 311, or without being deposited on theshutters 21 and 22. Thus, when the shutters 21 and 22 are opened afterthat (i.e., when this disc cartridge 311 has been loaded into a discdrive), no dust will be deposited on the signal recording side 100A ofthe disc 100.

The disc cartridge 311 may be left either upside up as shown in FIG. 50or upside down (i.e., with the lower shell 11 facing upward). In view ofthese two possible positions, the hole 20 h preferably has a diameterthat is approximately equal to that of the center hole 100 h. This isbecause if the holes 20 h and 100 h have approximately equal diameters,dust will be deposited neither on the shutters 21 and 22 when the disccartridge 311 is left upside up nor on the signal recording side 100A ofthe disc 100 when the disc cartridge 311 is left upside down.

In this disc cartridge 311, the opener/closer 22 t for use to open andclose the shutters 21 and 22 is provided for the shutter 22 unlike theeighth preferred embodiment described above. More specifically, as shownin FIGS. 51 and 57, the opener/closer 22 t, elastic portion 22 v andlocking protrusion 22 k are provided as integral parts of the shutter22. The locking protrusion 22 k is connected to the shutter 22 by way ofthe elastic portion 22 v as shown in FIG. 57. Accordingly, unlike theeighth preferred embodiment described above, the opener/closer 22 t islocated on the right-hand side of the head opening 11 h with respect tothe disc 100. The opener/closer 22 t operates in the same way as thecounterpart of the eighth preferred embodiment described above.

Embodiment 12

Hereinafter, a disc cartridge 312 according to a twelfth specificpreferred embodiment of the present invention will be described withreference to the accompanying drawings.

Unlike the disc cartridge 311 of the eleventh preferred embodimentdescribed above, the disc cartridge 312 of this twelfth preferredembodiment includes a rim 12 t around the inner side surface 12 i of thecartridge body 10 and a ring 20 w around the hole 20 h defined by theshutters 21 and 22. These features will be described below.

As shown in FIG. 58, the rim 12 t protrudes from the inner side surface12 i of the upper shell 12 toward the inner periphery of the disc 100and substantially surrounds the outer periphery of the disc storageportion 10 d. FIG. 59 shows a cross section of the disc cartridge 312 ina state where the disc 100 is stored in the disc storage portion 10 d.While the shutters 21 and 22 are closed, the outer edge of the signalrecording side 100A of the disc 100 contacts with the rim 12 t as shownin FIG. 59. As a result, the gap between the outer periphery of the disc100 and the cartridge body 10 is closed, thereby preventing dust fromreaching the signal recording side 100A of the disc 100.

Also, a gap 10 w is provided between the rim 12 t of the cartridge body10 and the lower shell 11. Thus, when the shutters 21 and 22 are opened,respective portions of the shutters 21 and 22 enter the gap 10 w asshown in FIGS. 60 and 61, thereby preventing the shutters 21 and 22 frominterfering with the cartridge body 10.

In such a structure, however, while the shutters 21 and 22 are closed,another gap 10 z that leads to the open air is also created between thedisc 100 and the shutters 21 and 22 as shown in FIG. 59. To close thisgap 10 z, the shutters 21 and 22 include convex portions 21 w and 22 w,respectively, around the center hole 100 h of the disc 100. As shown inFIG. 58, when the shutters 21 and 22 are closed, these two convexportions 21 w and 22 w are in tight contact with each other, therebyforming the ring 20 w that closes the gap 10 z around the disc centerhole 100 h. As a result, no dust will reach the signal recording side100A of the disc 100 through the disc center hole 100 h.

However, the top of these convex portions 21 w and 22 w might contactwith the signal recording side 100A of the disc 100. Accordingly, theedge of the convex portions 21 w and 22 w should preferably be round soas not to scratch the signal recording side 100A of the disc 100.Optionally, the convex portions 21 w and 22 w may form integral parts ofthe shutters 21 and 22, respectively. In that case, an anti-scratchingnonwoven fabric is preferably adhered or ultrasonic welded to thatportion of the ring 20 w that contacts with the signal recording side100A of the disc 100 or an anti-scratching coating is preferably formedon that portion. Alternatively, the convex portions 21 w and 22 wthemselves may be made of an anti-scratching nonwoven fabric or ananti-scratching coating and directly adhered or ultrasonic welded to theshutters 21 and 22, respectively.

Also, as shown in FIG. 59, while the shutters 21 and 22 are closed, thedisc 100 is lifted by the ring 20 w and the rim 12 t over the shutters21 and 22 with the gap 10 z left between them. That is to say, most ofthe signal recording side 100A of the disc 100 is not in contact withthe shutters 21 and 22. Accordingly, even if the surface of the shutters21 and 22 is not covered with an anti-scratching nonwoven fabric, forexample, the signal recording side 100A still will not get scratched.

FIGS. 62 and 63 illustrate a disc cartridge including alternative convexportions 21 w′ and 22 w′ that have been expanded toward the outerperiphery of the disc 100. Specifically, FIG. 62 illustrates a state inwhich the shutters 21 and 22 are closed, while FIG. 63 illustrates astate in which the shutters 21 and 22 are opened.

As shown in FIGS. 62 and 63, while the shutters 21 and 22 are opened,the convex portions 21 w′ and 22 w′ are preferably located inside therim 12 t of the disc storage portion 10 d (i.e., closer to the center ofthe disc storage portion 10 d). Then, the convex portions 21 w′ and 22w′ will not contact with, or interfere with, the rim 12 t.

Optionally, the convex portions 21 w′ and 22 w′ may form integral partsof the shutters 21 and 22, respectively. In that case, ananti-scratching nonwoven fabric is preferably adhered or ultrasonicwelded to those portions of the convex portions 21 w′ and 22 w′ thatcontact with the disc 100 or an anti-scratching coating is preferablyformed thereon. Alternatively, the convex portions 21 w′ and 22 w′themselves may be made of an anti-scratching nonwoven fabric or ananti-scratching coating and directly adhered or ultrasonic welded to theshutters 21 and 22, respectively.

Embodiment 13

Hereinafter, a disc cartridge 313 according to a thirteenth specificpreferred embodiment of the present invention will be described withreference to the accompanying drawings.

First, the structure of the disc cartridge 313 will be outlined withreference to FIGS. 64 and 65. As in the eighth preferred embodiment, thedisc 100 shown in FIGS. 64 and 65 also includes first and second sides.The first side of the disc 100, on which its label is normally printed,is illustrated in FIG. 64, while the second side thereof, i.e., thesignal recording side 100A, is illustrated as the backside in FIG. 65.

As shown in FIGS. 64 and 65, the disc cartridge 313 includes a lowershell 11, an upper shell 12, a pair of shutters 21 and 22 and discstoppers 23.

As shown in FIG. 65, the lower shell 11 includes a chucking opening 11 cand a head opening 11 h. The chucking opening 11 c allows a chuckingmember (e.g., a spindle motor for rotating the disc 100) to enter thedisc cartridge 313 externally. The head opening 11 h allows a head,which reads and/or writes a signal from/on the signal recording side100A of the disc 100, to enter the disc cartridge 313 and access atarget location on the disc 100. The lower shell 11 faces the signalrecording side 100A of the disc 100. The lower shell 11 is formed bymolding a synthetic resin into a predetermined shape.

The head opening 11 h reaches one side surface of the lower shell 11. Tominimize a decrease in rigidity of the lower shell 11 due to thepresence of the head opening 11 h, the lower shell 11 includes a bridge11 b that links both ends of the head opening 11 h together. The lowershell 11 further includes two positioning holes 11 w that engage withcartridge positioning pins (not shown) of a disc drive.

The upper shell 12 includes a circular disc window 12 w, through whichthe disc 100 can be introduced and removed into/from the disc cartridge313 and which expands over the entire projection area of the disc 100 toexpose the upper side of the disc 100. The upper and lower shells 12 and11 are adhered or welded together at their outer periphery, therebyforming a cartridge body 10. The upper shell 12 is also made of asynthetic resin.

A disc storage portion 10 d for storing the disc 100 therein is definedby an inner lower surface 11 u and an inner side surface 12 i of thecartridge body 10. The inner lower surface 11 u is opposed to the signalrecording side 100A of the disc 100, while the inner side surface 12 ihas a substantially cylindrical shape and defines the disc window 12 winside. That is to say, the inner lower surface 11 u is the bottom ofthe disc storage portion 10 d.

In the disc storage portion 10 d, a gap, which is wide enough to allowthe disc 100 to rotate freely, is provided between the inner sidesurface 12 i and the outer periphery of the disc 100. Also, the top ofthe disc storage portion 10 d is the disc window 12 w so that the disc100 stored in the disc storage portion 10 d has one of its sides exposedinside the disc window 12 w.

Two removable disc stoppers 23 are provided for the upper shell 12 so asto partially protrude into the disc window 12 w as shown in FIGS. 64 and65. A third disc stopper 12 s is further provided for the upper shell 12so as to protrude into the disc window 12 w. The third disc stopper 12 sforms an integral part of the upper shell 12. These three disc stoppers23 and 12 s are arranged substantially at regular intervals around thecircumference of the disc window 12 w for the purpose of preventing thedisc 100 from dropping down from the disc window 12 w. Also, two convexdisc contact portions 12 s are formed on the disc stopper 12 s. For thedisc 100, these disc contact portions 12 s′ are almost as high as thedisc contact portions 23 a of the disc stoppers 23.

According to this structure, even if the disc cartridge 313 is mountedvertically or upside down, the disc cartridge 313 still can hold thedisc 100 without dropping it. That is to say, when the disc cartridge313 is inserted vertically or upside down into a disc drive, this disccartridge 313 can particularly effectively prevent the disc 100 fromdropping down. It should be noted that the disc stoppers 23 do not haveto be removable from the cartridge body 10. Alternatively, as long asthe disc stoppers 23 can be rotated or bent inside the disc storageportion 10 d to such an extent as to allow the user to remove the disc100 from the cartridge body 10, the disc stoppers 23 may also be securedto the upper shell 12.

The shutters 21 and 22 lie on a single plane between the signalrecording side 100A of the disc 100 and the inner lower surface 11 u ofthe cartridge body 10. The shutters 21 and 22 include shaft holes 21 uand 22 u, respectively. These shaft holes 21 u and 22 u are engaged in afreely rotatable state with shafts 11 s, which are located outside ofthe disc storage portion 10 d of the cartridge body 10 and on a deepside of the cartridge body 10 opposite to the head opening 11 h thereof.Thus, the shutters 21 and 22 rotate on the shafts 11 s in such a manneras to cover or expose the chucking and head openings 11 c and 11 h. Theshutters 21 and 22 are also made of a synthetic resin.

A ring portion 21 c and a pin portion 22 c are provided near the shaftholes 21 u and 22 u of the shutters 21 and 22, respectively. The ringportion 21 c and the pin portion 22 c have mutually engaging shapes andtogether make up an interlocking mechanism 20 c for opening and closingthe shutters 21 and 22 while interlocking them with each other. Theinterlocking mechanism 20 c may also be implemented as a cam mechanismor a gear mechanism.

The respective upper surfaces of the shutters 21 and 22, which areopposed to the signal recording side 100A of the disc 100, are coveredwith protective layers 21 p and 22 p for the purpose of preventing thesignal recording side 100A of the disc 100 from getting scratched orattracting dust.

The protective layers 21 p and 22 p may be appropriately selected fromthe group consisting of anti-scratching nonwoven fabric, dustproofnonwoven fabric, anti-scratching coating and dustproof coating. In thispreferred embodiment, sheets of a dustproof nonwoven fabric are adheredor ultrasonic welded as the protective layers 21 p and 22 p to theshutters 21 and 22, respectively.

A locking protrusion 21 k is provided for the shutter 21, while alocking engaging portion 22 k, which engages with the locking protrusion21 k, is provided for the shutter 22. The locking protrusion 21 k andlocking engaging portion 22 k together make up a locking mechanism 20 kfor locking and unlocking the shutters 21 and 22 to/from each other. Byusing this mechanism 20 k, the shutters 21 and 22 can be locked andunlocked automatically, thus preventing the user from opening theshutters 21 and 22 accidentally. In addition, the signal recording side100A of the disc 100 can be protected from dust, finger marks orscratches. The locking protrusion 21 k and the locking engaging portion22 k form integral parts of the shutters 21 and 22, respectively.

Furthermore, the shutters 21 and 22 are provided with notches 21 h and22 h, respectively. When the shutters 21 and 22 are closed, thesenotches 21 h and 22 h contact with each other to form a hole 20 h justunder the center hole 100 h of the disc 100. In this case, the diameterof the hole 20 h is approximately equal to that of the center hole 100 hof the disc 100. In such a structure, even if this disc cartridge 313 isleft with the upper side of the disc 100 exposed upward, no dust will bedeposited on the shutters 21 and 22. Also, even if the disc cartridge313 is left upside down, no dust will be directly deposited on thesignal recording side 100A of the disc 100, either.

As already described for the eighth preferred embodiment, the shutters21 and 22 each include two disc holders 21 a, 21 b and 22 a, 22 b atboth ends thereof. These disc holders 21 a, 21 b, 22 a and 22 b arearranged substantially at regular intervals around the circumference ofthe disc 100. The disc holders 21 a, 21 b, 22 a and 22 b form integralparts of the shutters 21 and 22. Each of these disc holders 21 a, 21 b,22 a and 22 b has a downwardly tapered cross-sectional shape (or slope)to grip the outer edge of the disc 100 thereon when the shutters 21 and22 are closed. By providing these slopes, the disc 100 can be heldfirmly and pressed against the shutters 21 and 22 while the shutters 21and 22 are closed.

In this preferred embodiment, only the disc holder 21 b is not securedto the shutter 21 but is connected thereto via an elastic portion 21 dand is freely rotatable in the radial direction of the disc 100 (i.e.,toward the center of the disc 100). Accordingly, the disc holders 21 a,21 b, 22 a and 22 b can firmly hold a disc 100 having any of variousdiameters or thicknesses without allowing the disc 100 to moveinconstantly.

A shutter opener/closer 22 t for use to open and close the shutter 22 isformed as an integral part of the shutter 22 on the front side of thedisc cartridge 313 opposite to the shaft hole 22 u, i.e., near the discholder 22 a. When the shutters 21 and 22 are attached to the cartridgebody 10, the shutter opener/closer 22 t is located under the bridge 11 band inside the head opening 11 h. In opening or closing the shutters 21and 22, the opener/closer 22 t is moved along the bridge 11 b inside thehead opening 11 h. In this arrangement, there is no need to separatelyprovide any gap for allowing the shutter opener/closer 21 t to movetherein for the cartridge body 10. In other words, since there is noneed to provide an extra gap for the cartridge body 10, no dust willenter the cartridge body 10 unnecessarily. Furthermore, the shutteropener/closer 22 t can be disposed inside the head opening 11 h of thecartridge body 10, thus providing a cartridge of a simplified gooddesign.

As shown in FIG. 66, when closed, the shutters 21 and 62 are notentirely in contact with each other along a line but have a plurality ofcontact portions that are not aligned with the line. More specifically,the shutters 21 and 22 have a first pair of contact portions 21 f and 22f over the chucking opening 11 c and a second pair of contact portions21 g and 22 g over the head opening 11 h, respectively. In thispreferred embodiment, the contact portions 21 f and 22 f contact witheach other along the centerline of the disc cartridge 313. On the otherhand, the contact portions 21 g and 22 g contact with each other along aline that defines a predetermined angle (e.g., approximately 15 degreesto approximately 16 degrees) with the centerline of the disc cartridge313. When the shutters 21 and 22 have such shapes, the shutter 22 canhave an integral shape from the vicinity of the shutter opener/closer 22t and can exhibit sufficiently high rigidity.

Shutter springs 31 and 32 are provided outside of the disc storageportion 10 d for the shutters 21 and 22, respectively. These springs 31and 32 apply an elastic force to the shutters 21 and 22 in such adirection as to close the shutters 21 and 22. The shutter springs 31 and32 are inserted into two spring poles 11 t on the inner lower surface 11u of the cartridge body 10. In this preferred embodiment, torsion coilsprings are used as the shutter springs 31 and 32. The torsion coilsprings 31 and 32 preferably have the same shape to reduce the cost.Examples of other elastic members that may be used as the shuttersprings 31 and 32 include compression springs, leaf springs and elasticresin springs.

As shown in FIG. 65, the disc cartridge 313 includes a write protector40, which is inserted into a groove 11 v of the lower shell 11 so as toslide along the groove 11 v. By sliding the write protector 40, theconvex portion 40 t can be moved, thereby turning ON or OFF a sensorswitch provided for a disc drive. In this manner, writing on the disc100 may be either prohibited or allowed.

That is to say, this disc cartridge 313 is made up of the cartridge body10 consisting of the lower and upper shells 11 and 12, disc stoppers 23,shutters 21 and 22, shutter springs 31 and 32, and write protector 40.

When the lower and upper shells 11 and 12 are joined together, the twoshafts 11 s of the lower shell 11 are engaged with two concave portions12 h of the upper shell 12. In this manner, the shafts 11 s can havetheir rigidity increased. Thus, even when the shutters 21 and 22 areopen, reduced torsion is created at the respective centers of rotationof the shutters 21 and 22 by the elastic force applied from the shuttersprings 31 and 32. As a result, the shutters 21 and 22 can be opened tothe intended angle.

As shown in FIG. 64, the upper surface of the cartridge body 10 (or theupper shell 12) has a label plane 10 f, on which the user can note downthe contents of the disc 100 stored, and an embossed arrow mark (orconcave portion) 10 a that indicates the direction (the arrow 1A) inwhich this disc cartridge 313 should be inserted into a disc drive.

The cartridge body 10 further includes two pairs of concave portions 10c and 10 e on two of its side surfaces that are parallel to thedirection 1A in which the disc cartridge 313 is inserted. These concaveportions 10 c and 10 e may be used as either pull-in notches orpositioning recesses when the disc cartridge 313 is pulled in and loadedinto a disc drive or when the disc cartridge 313 is stored in a discchanger. The cartridge body 10 further includes a slit 10 b on one ofits side surfaces. The slit 10 b may be used as a recess to identify theupside and downside of the disc cartridge 313 from each other when thisdisc cartridge 313 is inserted into the disc drive.

Hereinafter, it will be described with reference to FIGS. 66, 67, 68 and69 how this disc cartridge 313 operates. FIGS. 66 and 67 are plan viewsillustrating the disc cartridge 313 in a state where its shutters 21 and22 are closed and in a state where its shutters 21 and 22 are opened,respectively. FIG. 68 is a plan view illustrating the details of theshutter locking mechanism 20 k. And FIG. 69 is a cross-sectional viewillustrating the details of the disc holder 22 a of the shutter 22.

First, a storage state of the disc cartridge 313, i.e., a state of thedisc cartridge 313 that has not been loaded into a disc drive yet, willbe described. In that state, the shutters 21 and 22 are closed as shownin FIG. 66. Also, as shown in FIG. 69, the slope 22 a′ of the discholder 22 a of the shutter 22 contacts with the outer edge of the disc100, thereby holding the disc 100 thereon and pressing the disc 100 inthe thickness direction 100 t. As a result, the signal recording side100A of the disc 100 is brought into contact with the sheet 22 p of theshutter 22 and the disc 100 is fixed in the cartridge body 10. The threeother disc holders 21 a, 21 b and 22 b also have their own slopes 21 a′,21 b′ and 22 b′, respectively. Thus, just like the disc holder 22 a,these disc holders 21 a, 21 b and 22 b also hold and fix the disc 100 inthe cartridge body 10.

In this state, the signal recording side 100A of the disc 100 is inclose contact with the sheets 21 p and 22 p. Thus, no dust will bedeposited on the signal recording side 100A. Also, if the exposed sideof the disc 100 is rotated manually or if the shutters 21 and 22 areopened or closed intentionally, then dust, finger marks or any otherdirt that has adhered onto the signal recording side 100A of the disc100 may be wiped away.

Furthermore, since the shutters 21 and 22 are locked by the lockingmechanism 20 k, the user cannot open the shutters 21 and 22accidentally. Thus, the signal recording side 100A of the disc 100 canbe protected from dust, finger marks or scratches.

Furthermore, the shutters 21 and 22 are provided with notches 21 h and22 h, respectively. When the shutters 21 and 22 are closed, thesenotches 21 and 22 contact with each other to form a hole 20 h just underthe center hole 100 h of the disc 100. In such a structure, even if thisdisc cartridge 313 is left with the upper side of the disc 100 exposedupward, dust will pass through the center hole 100 h but will not bedeposited on the shutters 21 and 22.

Also, while the shutters 21 and 22 are closed, at least the two pairs ofcontact portions 21 f, 22 f and 21 g, 22 g of the shutters 21 and 22,which are butted with each other over the chucking and head openings 11h and 11 c, respectively, each overlap with each other in the thicknessdirection of the disc 100 as shown in FIGS. 70 and 71. Accordingly, evenif the shutters 21 and 22 have been closed incompletely because a disc100 having a non-regular diameter has been mounted on this disccartridge 313 or because the shutters 21 and 22 have not been lockedcompletely, no gap will be created between the contact portions of theshutters 21 and 22. Thus, even in such a situation, the disc 100 canalso be protected from dust, finger marks or scratches.

Also, as shown in FIG. 70, the shutters 21 and 22 are in contact witheach other around the head opening 11 h so that the contact portion 22 gof the shutter 22 is located over the contact portion 21 g of theshutter 21. On the other hand, as shown in FIG. 71, the shutters 21 and22 are in contact with each other around the chucking opening 11 c sothat the contact portion 21 f of the shutter 21 is located over thecontact portion 22 f of the shutter 22. In this manner, the angledefined by one of multiple contact portions 21 f or 21 g or 22 f or 22 gof the shutter 21 or 22 may be different from the angle defined byanother one of the contact portions 21 g or 21 f or 22 g or 22 f of theshutter 21 or 22. In such a structure, the two shutters 21 and 22 can betightly engaged with each other in the thickness direction of the disc100. Thus, neither the shutter 21 nor the shutter 22 will be raisedunintentionally. In addition, while the shutters 21 and 22 are closed,the contact portions of the shutters 21 and 22 can exhibit increasedrigidity.

In this preferred embodiment, the shutters 21 and 22 have the contactportions 21 f, 21 g, 22 f and 22 g shown in FIGS. 70 and 71. However,the shutters 21 and 22 may also have contact portions at differentlocations or may contact with each other in a different manner. Forexample, the contact portions 21 g and 22 g shown in FIG. 70 may beshifted to a location around the head opening 11 h or the contactportions 21 f and 22 f shown in FIG. 71 may be shifted to a locationaround the chucking opening 11 c. Then, the shutters 21 and 22 canexhibit even higher rigidity when closed, and the gap between thecontact portions can be further reduced, thus preventing the dust fromentering the inside of the cartridge.

Also, while the shutters 21 and 22 are closed, convex portions 21 j and22 j, provided for the shutters 21 and 22 as shown in FIG. 68, are incontact with two shutter stoppers 12 f provided for the upper shell 12as shown in FIG. 65. Accordingly, the shutters 21 and 22 have itsrotation regulated and cannot move from their locked positions. As aresult, the shutters 21 and 22 will not move inconstantly in theirlocked state. In addition, it is possible to prevent the user frombreaking the shutters 21 and 22 intentionally. Furthermore, since theshutters 21 and 22 have their rotation regulated, the shutteropener/closer 22 t is not displaced. Accordingly, when this disccartridge 313 is loaded into a disc drive, the shutter opener/closer 22t can be engaged with the shutter opening/closing mechanism of the discdrive just as intended.

Hereinafter, it will be described how this disc cartridge 313 is loadedinto the disc drive. As shown in FIG. 66, when the disc cartridge 313 isinserted into the disc drive in the direction 1A, the cartridgepositioning pins of the disc drive engage with the positioning holes 11w of the disc cartridge 313, thereby determining the horizontal andvertical positions of the disc cartridge 313 inside the disc drive.

Next, a shutter opener/closer of the shutter opening/closing mechanismprovided inside the disc drive engages with the shutter opener/closer 22t shown in FIG. 68. At the same time, an unlocking member of the shutteropening/closing mechanism presses an unlocking portion 21 y, which isconnected to the shutter 21 by way of an elastic portion 21 e, in thedirection 20A. As a result, the locking protrusion 21 k of the lockingmechanism 20 k is disengaged from the locking engaging portion 22 kthereof, thereby unlocking the shutters 21 and 22 from each other. Insuch a state, the shutter opener/closer of the shutter opening/closingmechanism moves the shutter opener/closer 22 t in the directionindicated by the arrow 20B. Consequently, the shutter 21 rotates on theshaft 11 s while dominating the elastic force applied from the shutterspring 31 as shown in FIG. 67. Synchronously with the movement of theshutter 21, the other shutter 22, which is interlocked with the formershutter 21 via the interlocking mechanism 20 c, also rotates whiledominating the elastic force applied from the shutter spring 32.Accordingly, when the shutter 21 has been opened, the shutter 22 willhave also been opened.

By the time the shutters 21 and 22 are opened completely, the lockingprotrusion 21 k and the unlocking portion 21 y will have returned totheir home positions along with the elastic portion 21 e. Thus, theelastic portion 21 e made of a resin is not deformed plastically. Inthis manner, the signal recording side 100A of the disc 100 is exposedthrough the chucking and head openings 11 c and 11 h. Also, the disc100, which has been held by the disc holders 21 a, 21 b, 22 a and 22 b,is released therefrom as the shutters 21 and 22 rotate. As a result, thedisc 100 is now freely rotatable inside the disc storage portion 10 d.

Subsequently, the spindle motor and the turntable of the disc driveenter the chucking opening 11 c and the head of the disc drive entersthe head opening 11 h. Consequently, the disc drive is now ready toperform a read or write operation on the disc 100 loaded.

As described above, only by getting the locking protrusion 21 k pressedexternally by a protrusion, for example, in the direction indicated bythe arrow 20A and disengaged from the locking engaging portion 22 kwhile pressing the shutter opener/closer 22 t in the direction indicatedby the arrow 20B at the same time, the shutters 21 and 22 can be rotatedto expose the chucking and head openings 11 c and 11 h and the disc 100can be released from the disc holders 21 a, 21 b, 22 a and 22 b. Thus,it is possible to prevent the user from opening the shutters 21 and 22or removing the disc 100 accidentally. As a result, the disc 100 can beprotected from dust, finger marks or scratches.

Hereinafter, it will be described how the disc cartridge 313 is ejectedfrom the disc drive. When an ejecting mechanism of the disc drive startsto operate, the shutter opener/closer of the disc drive, which has beenengaged with the shutter opener/closer 22 t, disengages itself from theshutter opener/closer 22 t. As a result, the shutters 21 and 22 cannotbe kept opened and start to rotate in the opposite direction. That is tosay, the shutters 21 and 22, to which an elastic force is being appliedfrom the shutter springs 31 and 32 in such a direction as to close theshutters 21 and 22, start to close themselves. Consequently, theshutters 21 and 22 close up the head and chucking openings 11 h and 11c. In this case, the shutters 21 and 22 are locked to each other by thelocking mechanism 20 k. In the meantime, the disc 100 gets held by thedisc holders 21 a, 21 b, 22 a and 22 b again to recover its originalstate. Then, the disc cartridge 313 is ejected from the disc drive.

In the disc cartridge 313, the disc contact portion 23 a of the discstoppers 23 provided for the cartridge body 10 and the disc contactportion 12 s′ of the upper shell 12 are located at the same verticallevel as shown in FIG. 69. Also, the top of the slopes 21 a′, 21 b′, 22a′ and 22 b′ of the disc holders 21 a, 21 b, 22 a and 22 b of theshutters 21 and 22 is higher in level than the bottom of the disccontact portions 23 a and 12 s′ in the direction 100 u in which the disc100 is movable. Accordingly, even if the disc cartridge 313 is loadedinto a disc drive either vertically or upside down, the shutters 21 and22 still can hold the disc 100 firmly thereon. For example, if the disccartridge 313 is loaded upside down into a disc drive, the disc 100 thatis no longer chucked contacts with the disc contact portions 23 a and 12s′ and still can maintain its horizontal position. And when the shutters21 and 22 are closed in such a state, the disc 100 contacts with theslopes 21 a′, 21 b′, 22 a′ and 22 b′ this time. Then, the disc 100 willslide along the slopes 21 a′, 21 b′, 22 a′ and 22 b′ smoothly to be heldfirmly by the disc holders 21 a, 21 b, 22 a and 22 b.

In the disc cartridge of the thirteenth preferred embodiment describedabove, the cartridge body thereof has a disc window and covers only oneside of the disc. Also, the disc cartridge includes a shutteropener/closer inside a head opening of the cartridge body, andtherefore, there is no need to provide an unnecessary gap for thecartridge body. As a result, no dust will enter the inside of thecartridge body.

In addition, in the disc cartridge of this thirteenth preferredembodiment, the two shutters thereof are made to contact with each otheralong the centerline of the disc over the chucking opening and along aline, which defines a predetermined angle with the centerline, over thehead opening. Accordingly, these shutters can have an integratedstructure from the vicinity of the shutter opener/closer and can exhibitsufficiently high rigidity.

Furthermore, since the two shutters are locked or unlocked to/from eachother, the user cannot open or close the shutters accidentally. Thus,the disc can be protected from dust, finger marks or scratches.

Moreover, at least one of multiple disc holders of the disc cartridge isnot secured to its associated shutter but is just connected thereto viaan elastic portion. As an elastic force is also applied from a shutterspring to that disc holder, the disc holder can be deformed sufficientlyelastically in the disc radial direction. For that reason, even if adisc of a non-regular size has been mounted on this disc cartridge, thedisc cartridge can also hold such a disc firmly without allowing it tomove inconstantly.

Embodiment 14

Hereinafter, a disc cartridge 314 according to a fourteenth specificpreferred embodiment of the present invention will be described withreference to FIGS. 72 through 81. In FIGS. 72 through 81, each member ofthe disc cartridge 314 of the fourteenth preferred embodiment, havingsubstantially the same function as the counterpart of the disc cartridge313 of the thirteenth preferred embodiment described above, isidentified by the same reference numeral.

The disc cartridge 314 of the fourteenth preferred embodiment isdifferent from the disc cartridge 313 of the thirteenth preferredembodiment described above in the respective shapes of the inner uppersurface 12 u of the cartridge body 10 (see FIG. 79), the disc holders 21a, 21 b, 22 a and 22 b (see FIGS. 72 through 79) and the disc stoppers53 (see FIGS. 72, 77 and 78). In addition, the disc cartridge 314further includes a disc supporting portion 60 (see FIGS. 72 and 81).Thus, the following description of the disc cartridge 314 of thefourteenth preferred embodiment of the present invention will be focusedon these differences.

In the disc cartridge 313 of the thirteenth preferred embodimentdescribed above, the respective tops of the disc holders 21 a, 21 b, 22a and 22 b thereof are located at substantially the same vertical levelsalong the outer periphery of the disc 100. In contrast, in the disccartridge 314 of this fourteenth preferred embodiment, protrusions areformed on predetermined areas of the disc holders 21 b, 22 a and 22 b asshown in FIGS. 73 and 79. More specifically, as shown in FIG. 79, eachof these three disc holders 21 b, 22 a and 22 b includes: a firstportion 121 b, 122 a or 122 b that has a protrusion thereon and has afirst height h1 as measured from the upper surface of the shutters 21and 22; and a second portion 221 b, 222 a or 222 b that has a secondheight h2 as measured from the upper surface of the shutters 21 and 22.The other disc holder 21 a consists of a second portion 221 a that hasthe second height h2.

The first height h1 is greater than the second height h2 and isapproximately equal to the height (i.e., the vertical level of the uppersurface) of the disc holders 21 a, 21 b, 22 a and 22 b of the disccartridge 313 of the thirteenth preferred embodiment described above.That is to say, the disc holders 21 a, 21 b, 22 a and 22 b of thisfourteenth preferred embodiment are lower than the counterparts of thedisc cartridge 313 of the thirteenth preferred embodiment except theirfirst portions 121 b, 122 a and 122 b.

Also, as shown in FIGS. 74 and 75, a stepped protrusion 223 is formed onthe upper surface of the first portion 122 a of the disc holder 22 a.The stepped protrusion 223 has two vertical levels, the higher one ofwhich is closer to the disc 100 mounted. A similar stepped protrusion isalso formed on the upper surface of the first portion 121 b of the discholder 21 b and on the upper surface of the first portion 122 b of thedisc holder 22 b.

As the shutter 21 or 22 is getting closed, the first portion 121 b, 122a or 122 b of the disc holder 21 b, 22 a or 22 b contacts with the disc100 earlier than any other portion thereof (i.e., earlier than thesecond portion 221 b, 222 a or 222 b thereof).

The disc holders 21 a, 21 b, 22 a and 22 b move as the shutters 21 and22 are opened or closed. FIG. 77 illustrates the respective positions ofthe disc holders 21 a, 21 b, 22 a and 22 b while the shutters 21 and 22are closed. On the other hand, FIG. 78 illustrates the respectivepositions of the disc holders 21 a, 21 b, 22 a and 22 b while theshutters 21 and 22 are opened. FIGS. 79 and 80 are cross-sectional viewsillustrating portions of the disc cartridge 314 that are respectivelyviewed along the lines B-B and C-C shown in FIG. 78.

As shown in FIGS. 77, 78 and 79, the regions 12 y, 12 x and 12 z on theinner upper surface 12 u of the cartridge body 10, through which thefirst portions 121 b, 122 a and 122 b of the disc holders 21 b, 22 a and22 b pass as the shutters 21 and 22 are opened or closed, are recessed.On the other hand, the regions 12 y′, 12 x′ and 12 z′, through which thesecond portions 221 b, 222 a and 222 b thereof pass, are not recessed.Accordingly, the upper shell 12 is thinner in the regions 12 x, 12 y and12 z than in the regions 12 x′, 12 y′ and 12 z′.

As shown in FIGS. 76 and 79, the top of the first portion 122 a of thedisc holder 22 a is located at a vertical level higher than the bottomof the disc stopper 53. Also, the top of the first portion 122 a of thedisc holder 22 a is received by the recessed first region 12 x on theinner upper surface 12 u. Since the stepped protrusion 223 is formed atthe top of the first portion 122 a, just a part of the upper surface ofthe first portion 122 a is in contact with the inner upper surface 12 u.On the other hand, the second portion 222 a of the disc holder 22 a isnot in contact with the inner upper surface 12 u.

To open and close the shutters 21 and 22 smoothly, the friction causedby the contact between the top of the first portion 122 a of the discholder 22 a and the inner upper surface 12 u is preferably small. Forthat purpose, the top of the first portion 122 a of the disc holder 22 ahas an arc-shaped cross section when taken in the radial direction ofthe disc 100. This stepped protrusion 223 is provided to compensate forshortage in mechanical strength, which would be caused by a sharpenedtop of the first portion 122 a, and to make that top moldable moreaccurately and more easily.

As shown in FIG. 80, the top of the first portion 122 b of the discholder 22 b is also located at a vertical level higher than the bottomof the disc stopper 53. And the top of the first portion 122 b of thedisc holder 22 b is received by the recessed first region 12 z on theinner upper surface 12 u. Although not shown, the top of the firstportion 121 b of the disc holder 21 b is also located at a verticallevel higher than the bottom of the disc stopper 53, and is received bythe recessed first region 12 y on the inner upper surface 12 u.

As described above, in the disc cartridge 314 of the fourteenthpreferred embodiment, the regions 12 x, 12 y and 12 z on the inner uppersurface 12 u are recessed to receive portions of the disc holders 22 a,21 b and 22 b, respectively. Thus, the thickness of the disc cartridge314 can be reduced by the depth of those recessed regions 12 x, 12 y and12 z.

Even if the disc cartridge 314 having such a structure is loaded into adisc drive either vertically or upside down, the disc 100 that is nolonger chucked never fails to contact with the slope 122 a′ of the firstportion 122 a of the disc holder 22 a as shown in FIG. 79 as theshutters 21 and 22 are closed. Thereafter, the disc 100 will slidesmoothly along the slope 122 a′ to contact with the slope 222 a′ of thesecond portion 222 a of the disc holder 22 a (see FIG. 74). At the sametime, the disc 100 also contacts with the slope 221 a′ of the secondportion 221 a of the disc holder 21 a. In this manner, the disc holders21 a and 22 a hold the disc 100 thereon cooperatively. The two otherdisc holders 21 b and 22 b also hold the disc 100 thereon throughsimilar operations. Accordingly, although this disc cartridge 314 has areduced thickness, the disc cartridge 314 can close the shutters 21 and22 in any position and can hold the disc 100 thereon just as intended.

If this disc cartridge had its thickness just reduced without changingthe shapes of the disc holders (or using the disc holders of thethirteenth preferred embodiments as they are), the regions 12 x, 12 x′,12 y, 12 y′, 12 z and 12 z′ on the inner upper surface 12 u, throughwhich the disc holders 22 a, 21 b and 22 a pass, should all be recessedas can be seen from FIG. 78. In that case, the upper shell 12 would havea reduced thickness over a rather wide area and such a disc cartridgewould have a decreased mechanical strength. In contrast, the disccartridge 314 of this fourteenth preferred embodiment can have itsthickness reduced without decreasing its mechanical strength because theregions 12 x, 12 y and 12 z with a reduced thickness are relativelynarrow.

In the preferred embodiment described above, three protrusions areprovided for three of the four disc holders. However, the number ofprotrusions to be provided is changeable with the number of disc holdersor the shapes of the shutters.

The disc cartridge 314 of the fourteenth preferred embodiment is alsodifferent from the disc cartridge 313 of the thirteenth preferredembodiment in the shape of the disc stoppers 53.

As shown in FIG. 72, the disc stoppers 53 have the shape of a notchedcircular plate. Specifically, notches 54 having substantially the sameshape as the disc stoppers 53 are provided along the disc window 12 w ofthe upper shell 12 and the disc stoppers 53 are engaged in a rotatablestate with the notches 54. As shown in FIG. 77, the disc stoppers 53 areheld in such a manner as to partially protrude into the disc window 12 wof the upper shell 12 when rotated. Also, as shown in FIG. 78, byrotating the disc stoppers 53, the disc stoppers 53 may also be held insuch a manner as to be stored inside the upper shell 12 and not toprotrude into the disc window 12 w. If the disc stoppers 53 are easilydisengaged from the notches 54 unintentionally, then the side surfacesof the disc stoppers 53 and the notches 54 of the upper shell 12 mayhave mutually engaging concave and convex portions, for example.

In such a structure, the thickness of the disc stoppers 53 may besubstantially equal to that of the upper part of the upper shell 12.Thus, the disc cartridge 314 can have a reduced overall thickness.

The disc cartridge 314 of this fourteenth preferred embodiment is alsocharacterized by including a disc supporting portion 60 at the bottom ofthe inner periphery of the disc storage portion. The disc supportingportion 60 is located between the inner lower surface 11 u and the innerside surface 11 l of the cartridge body 10 as shown in FIGS. 72, 77, 78and 81. As shown in FIG. 81, the disc supporting portion 60 has an uppersurface 60 a, which is parallel to the inner lower surface 11 u of thecartridge body 10.

As also shown in FIG. 81, while the shutters 21 and 22 are closed andthe disc 100 is held by the disc holders, the outer edge and itssurrounding portion of the signal recording side 100A of the disc 100are in contact with the upper surface 60 a of the disc supportingportion 60. Thus, no dust will be deposited on the signal recording side100A of the disc 100 or accumulated on the inner lower surface 11 u ofthe cartridge body 10.

Alternatively, the disc supporting portion 60 may have any shape otherthan that shown in FIG. 81. For example, as shown in FIG. 82, a discsupporting portion 76 having an upwardly tapered cross section may beformed between the inner lower surface 11 u and the inner side surface11 i of the cartridge body 10. In that case, while the shutters 21 and22 are closed and the disc 100 is held by the disc holders, the outeredge of the signal recording side 100A of the disc 100 is in contactwith the disc supporting portion 76.

Embodiment 15

Hereinafter, a disc cartridge 315 according to a fifteenth specificpreferred embodiment of the present invention will be described withreference to FIGS. 83 through 87. In FIGS. 83 through 87, each member ofthe disc cartridge 315 of the fifteenth preferred embodiment, havingsubstantially the same function as the counterpart of the disc cartridge314 of the fourteenth preferred embodiment described above, isidentified by the same reference numeral.

As shown in FIG. 83, unlike the disc cartridge 314 of the fourteenthpreferred embodiment described above, the disc cartridge 315 of thisfifteenth preferred embodiment includes four types of recesses 85, 86,87 and 88 a through 88 c. The recesses 85 are formed on the respectivelower surfaces 21 v and 22 v of the shutters 21 and 22. The other threetypes of recesses 86, 87 and 88 a through 88 c are formed on the innerlower surface 11 u of the cartridge body 10 that contacts with theshutters 21 and 22. These four types of recesses will be described belowone by one. Where the disc cartridge 315 is supposed to hold a dischaving a diameter of about 12 cm, these recesses may have a depth ofabout 0.1 mm to about 0.3 mm, for example.

As can be seen from FIGS. 84 and 85 illustrating two states of the disccartridge 315 in which its shutters 21 and 22 are closed and opened,respectively, the first type of recesses 86 are formed in respectiveregions of the inner lower surface 11 u that contact with the discholders 21 a, 21 b, 22 a and 22 b of the shutters 21 and 22 when theshutters 21 and 22 are opened or closed.

The disc holders 21 a, 21 b, 22 a and 22 b are sandwiched between theupper and lower shells 12 and 11 with almost no gap left between them.Accordingly, when respective members of the disc cartridge 315 areassembled together or if any of those members of the disc cartridge 315has a size that is greatly different from the designed one, the discholders 21 a, 21 b, 22 a and 22 b might contact with the upper and lowershells 12 and 11. In that case, excessive friction would be createdbetween the disc holders 21 a, 21 b, 22 a and 22 b and the upper orlower shell 12 or 11. As a result, the shutters 21 and 22 might beunable to be opened or closed so easily or dust might be stirred up dueto the excessive friction.

However, by providing the first type of recesses 86, gaps are providedunder the disc holders 21 a, 21 b, 22 a and 22 b, thus reducing suchunwanted friction. Then, the shutters 21 and 22 can always be opened orclosed smoothly and no dust will be stirred up due to the friction.

The second type of recesses 87 are formed in those regions of the innerlower surface 11 u where the respective outer edges of the shutters 21and 22 are located while the shutters 21 and 22 are closed. As shown inFIGS. 84 and 86, these recesses 87 preferably extend along the boundarythat defines the outer edges of the shutters 21 and 22 on the innerlower surface 11 u and are preferably present both inside and outside ofthe boundary.

This disc cartridge 315 is supposed to store the disc 100 therein withone side thereof exposed, and the user can press the disc 100 in thedirection indicated by the arrow A in FIG. 86. To protect the signalrecording side 100A of the disc 100, the respective upper surfaces ofthe shutters 21 and 22 are covered with the nonwoven fabrics 21 s and 22s but their outer edges are not completely covered with the nonwovenfabrics 21 s and 22 s. Accordingly, if the disc 100 is pressed in thedirection A, then the outer edges of the shutters 21 and 22 contact withthe signal recording side 100A of the disc 100, thus possibly scratchingthe signal recording side 100A as shown in FIG. 86.

However, if the second type of recesses 87 are provided, the shutters 21and 22 may be deformed in such a manner that the outer edges thereof arepartially forced into the second type of recesses 87. Then, the pressingforce can be dispersed, and the outer edges of the shutters 21 and 22will not be pressed against the signal recording side 100A of the disc100 too strongly.

The third type of recesses include: recesses 88 a that are formed on theinner lower surface 11 u so as to surround the chucking and headopenings 11 c and 11 h; recesses 88 b that are formed in those regionsof the inner lower surface 11 u that are not overlapped by the shutters21 and 22 when the shutters 21 and 22 are closed; and a recess 88 c thatis located in a region of the inner lower surface 11 u that isoverlapped by the shutters 21 and 22 when the shutters 21 and 22 areclosed. The recesses 88 b and 88 c are provided so as to draw a circlealong the circumference of the disc storage portion 10 d. In thispreferred embodiment, the number of the recesses 88 a of the third typeis three.

This disc cartridge 315 is also provided with various types ofstructures (e.g., a disc supporting portion) for preventing dust fromentering the disc cartridge 315 or being deposited on the signalrecording side 100A of the disc 100. However, it is actually difficultto totally eliminate the dust that enters the disc cartridge 315 or isdeposited on the signal recording side 100A.

Thus, the third type of recesses 88 a, 88 b and 88 c are provided toaccumulate the dust that has entered the disc cartridge 315.Specifically, as the shutters 21 and 22 are opened or closed, the dustis collected in these recesses 88 a, 88 b and 88 c of the third type.Once collected in the recesses 88 a, 88 b and 88 c, the dust nevercontacts with the shutters 21 and 22 and remains in the recesses 88 a,88 b and 88 c without going out of the recesses 88 a, 88 b and 88 c.Accordingly, by accumulating the dust in the third type of recesses 88a, 88 b and 88 c in this manner, the dust will not interfere withopening or closing of the shutters 21 and 22 or will be stirred up dueto an excessive friction.

It should be noted that these effects are also achievable by the firsttype of recesses 86 or the second type of recesses 87. Accordingly, thedisc cartridge 315 does not have to include all of these recesses 86,87, 88 a, 88 b and 88 c but may include just one type of recesses. Evenso, the shutters 21 and 22 will not be interfered with their opening orclosing by the dust and almost no dust will be stirred up due to afriction.

Also, to remove the dust from the gap between the shutters 21 and 22 andthe inner lower surface 11 u and accumulate it in the second type ofrecesses 87, for example, even more effectively, the respective lowersurfaces 21 v and 22 v of the shutters 21 and 22 may be provided withthe recesses 85 along the outer edges thereof. In that case, when theshutters 21 and 22 are closed, these recesses 85 are preferably locatedinside the second type of recesses 87 (i.e., closer to the centerline ofthe cartridge 315) as shown in FIG. 84. Also, as shown in FIG. 86, whenthe shutters 21 and 22 are closed, the recesses 85 of the shutters 21and 22 are preferably discontinuous with the second type of recesses 87on the inner lower surface 11 u.

When the shutters 21 and 22 have the recesses 85, the outer edges of theshutters 21 and 22 are deformed more easily. Accordingly, even when aforce is externally applied to the disc 100 in the direction A, theouter edges of the shutters 21 and 22 are deformed easily and will muchless likely press the signal recording side 100A of the disc 100 sostrongly as to scratch it. Optionally, these recesses 86, 87, 88 a, 88 band 88 c may have their inner faces covered with a nonwoven fabric thathas been adhered or welded thereto. Then, the gaps created by theserecesses inside the cartridge body can be filled and dust will enterthis disc cartridge 315 even less easily.

In the fifteenth preferred embodiment described above, the various typesof recesses are provided for the disc cartridge 314 of the fourteenthpreferred embodiment. Alternatively, these recesses may also be providedfor the disc cartridge according to any of the eighth through thirteenthpreferred embodiments of the present invention described above.

Embodiment 16

Hereinafter, a disc cartridge 316 according to a sixteenth specificpreferred embodiment of the present invention will be described withreference to FIGS. 88 through 93. In FIGS. 88 through 93, each member ofthe disc cartridge 316 of the sixteenth preferred embodiment, havingsubstantially the same function as the counterpart of the disc cartridge313 of the thirteenth preferred embodiment described above, isidentified by the same reference numeral.

As shown in FIG. 88, the disc cartridge 316 of this preferred embodimentincludes first and second opener/closers 22 t and 93 on first and secondside surfaces 10 p and 10 q of the cartridge body 10, respectively. Thefirst opener/closer 22 t is formed on the first side surface 10 p thatextends substantially vertically to the direction 1A in which this disccartridge 316 is inserted into a disc drive, while the secondopener/closer 93 is formed on the second side surface 10 q that extendssubstantially parallelly to the direction 1A. The first opener/closer 22t has the same structure as the shutter opener/closer 22 t of the disccartridge 313 of the thirteenth preferred embodiment.

As shown in FIG. 89, the second opener/closer 93 is formed in the shapeof a gear having a hole that can be inserted into a shaft 11 q providedfor the lower shell 11. A side surface of the lower shell 11 has anopening 11 r to expose a portion of the second opener/closer 93 throughthe second side surface 10 q of the cartridge body 10 when the secondopener/closer 93 is inserted into the shaft 11 q. Alternatively, theshaft 11 q may be provided for the upper shell 12.

The shutters 21 and 22 are also provided to expose or cover the head andchucking openings 11 h and 11 c of the lower shell 11. The shutters 21and 22 are equivalent to the second and first shutters as defined in theappended claims. The first opener/closer 22 t forms an integral part ofthe shutter 22. On the other hand, a sector gear 21 m, which engageswith the second opener/closer 93, is formed on the outer side surface ofthe shutter 21 and is located near the disc holder 21 b. The center ofrotation of the sector gear 21 m is the shaft hole 21 u of the shutter21. The outer side surface of the shutter 21 also has a concave portion21 n, which is adjacent to the sector gear 21 m. This concave portion 21n is formed to define a space in which the second opener/closer 93engages with the sector gear 21 m.

The shutters 21 and 22 may be opened or closed by using the firstopener/closer 22 t in the following manner. First, as shown in FIG. 90,the locking protrusion 21 k and the locking engaging portion 22 k, whichtogether make up the locking mechanism 20 k, are disengaged from eachother. Then, the first opener/closer 22 t is slid along the first sidesurface 10 p of the cartridge body 10 as indicated by the arrow 22W inFIG. 90. As a result, the other shutter 21 is also moved synchronouslywith the shutter 22 by way of the interlocking mechanism 20 c, and thesetwo shutters 21 and 22 expose the head and chucking openings 11 h and 11c as shown in FIG. 91.

The shutters 21 and 22 may also be opened by using the secondopener/closer 93 in the following manner. First, the locking mechanism20 k is unlocked as shown in FIG. 90. Next, the second opener/closer 93is rotated to the direction indicated by the arrow 93A. Then, the sectorgear 21 m gets engaged with the second opener/closer 93 and starts torotate on the shaft hole 21 u, thereby opening the shutter 21. Since theother shutter 22 is also moved synchronously with the shutter 21 by wayof the interlocking mechanism 20 c, these two shutters 21 and 22 exposethe head and chucking openings 11 h and 11 c. When the head and chuckingopenings 11 h and 11 c are completely exposed by the shutters 21 and 22as shown in FIG. 91, a portion of the second opener/closer 93 is locatedinside the concave portion 21 n of the shutter 21.

To close the shutters 21 and 22, the first opener/closer 22 t may beslid in the direction opposite to the direction 22W or the secondopener/closer 93 may be rotated to the direction opposite to thedirection 93A. In this preferred embodiment, the disc cartridge 316includes the shutter springs 31 and 32 that apply an elastic force tothe shutters 21 and 22 in such a direction as to close the shutters 21and 22. Accordingly, unless a force that is strong enough to open, orkeep opened, the shutters 21 and 22 against the elastic force of theshutter springs 31 and 32 is applied to the first or secondopener/closer 22 t or 93, the shutters 21 and 22 close themselvesautomatically.

In the disc cartridge 316 of the sixteenth preferred embodiment, theopener/closers are provided for the shutters 21 and 22 both on a sidesurface that is perpendicular to the direction in which this disccartridge 316 is inserted into a disc drive and on a side surface thatis parallel to the disc cartridge inserting direction. Accordingly, nomatter whether the disc drive used is compatible with only a disccartridge including a shutter opener/closer on a side surface thatextends perpendicularly to the disc cartridge inserting direction oronly a disc cartridge including a shutter opener/closer on a sidesurface that extends parallelly to the disc cartridge insertingdirection, the disc drive can always read or write a signal from/on thedisc stored in the disc cartridge of this preferred embodiment.

Also, in the disc cartridge 316 of this sixteenth preferred embodiment,the second opener/closer 93, provided for the side surface parallel tothe direction in which the disc cartridge 316 is inserted, has a gearshape. Accordingly, a shutter opening/closing mechanism to be providedfor the disc drive may also be any of various shapes of gears that canengage with the second opener/closer 93. Thus, the disc drive may use arelatively simple mechanism to open or close the shutters 21 and 22 ofthe disc cartridge 316.

In the preferred embodiment described above, the sector gear 21 m isprovided near the disc holder 21 b. This is because the distance betweenthe sector gear 21 m at such a position and the shaft hole 21 u of theshutter 21 is relatively short and because the sector gear 21 m needs tohave a relatively short length to open the shutter 21 fully. However,the sector gear 21 m does not have to be provided at this position.Alternatively, the sector gear 21 m and the second opener/closer 93 mayalso be provided at such positions as shown in FIGS. 92 and 93. In thealternative preferred embodiment shown in FIGS. 92 and 93, the sectorgear 21 m may be located at such a position that when extended, acircular trace drawn by the sector gear 21 m will substantiallyintersect with the center of the disc 100, while the secondopener/closer 93 may be provided at such a position as to engage withthe sector gear 21 m. When the second opener/closer 93 is provided atsuch a position, the sector gear 21 m should be relatively long to openthe shutter 21 fully, but the distance between the sector gear 21 m andthe shaft hole 21 u may also be relatively long. That is to say, sincethere is a long distance between the fulcrum and the application pointin that case, a lighter force is needed to rotate the secondopener/closer 93 and open or close the shutters 21 and 22.

Embodiment 17

Hereinafter, a disc cartridge 317 according to a seventeenth specificpreferred embodiment of the present invention will be described withreference to FIGS. 94 through 97. In FIGS. 94 through 97, each member ofthe disc cartridge 317 of the seventeenth preferred embodiment, havingsubstantially the same function as the counterpart of the disc cartridge316 of the sixteenth preferred embodiment described above, is identifiedby the same reference numeral.

As shown in FIG. 94, the disc cartridge 317 of this seventeenthpreferred embodiment includes a second opener/closer 94 on its secondside surface 10 q instead of the second opener/closer 93 of the disccartridge 316 of the sixteenth preferred embodiment described above.

As can be seen from FIG. 95, the second opener/closer 94 is a linkmember that can slide along the opening 11 r of the lower shell 11 andthat is bent approximately at the center thereof. Also, the secondopener/closer 94 includes a protrusion 94 a at one end thereof. Thisprotrusion 94 a engages with a groove 21 i that is provided on the uppersurface of the shutter 21 near the disc holder 21 b.

FIGS. 96 and 97 illustrate two states of the disc cartridge 317 in whichthe shutters 21 and 22 thereof are closed and opened, respectively. Asalready described for the thirteenth and sixteenth preferredembodiments, the shutters 21 and 22 can be opened or closed by slidingthe first opener/closer 22 t in the direction 22 w or in the oppositedirection.

The shutters 21 and 22 may also be opened by using the secondopener/closer 94 in the following manner. First, the locking mechanism20 k is unlocked as shown in FIG. 96. Next, the second opener/closer 94is slid in the direction indicated by the arrow 94B. As a result of thisoperation, a force is applied to the second opener/closer 94 in such adirection as to move the protrusion 94 a of the second opener/closer 94in the direction indicated by the arrow 94B. Thus, the shutter 21 isrotated on the shaft hole 21 u and opened. Since the other shutter 22 isalso moved synchronously with the shutter 21 by way of the interlockingmechanism 20 c, these two shutters 21 and 22 expose the head andchucking openings 11 h and 11 c. As in the sixteenth preferredembodiment described above, the shutters 21 and 22 can also be closed bysliding the second opener/closer 94 in the direction opposite to thedirection 94B, and the shutter springs 31 and 32 also apply an elasticforce to the shutters 21 and 22 in such a direction as to close theshutters 21 and 22.

Just like the disc cartridge 316 of the sixteenth preferred embodimentdescribed above, no matter whether the disc drive used is compatiblewith only a disc cartridge including a shutter opener/closer on a sidesurface that extends perpendicularly to the disc cartridge insertingdirection or only a disc cartridge including a shutter opener/closer ona side surface that extends parallelly to the disc cartridge insertingdirection, the disc drive can always read or write a signal from/on thedisc stored in the disc cartridge 317 of this preferred embodiment.

Also, as shown in FIGS. 96 and 97, the direction 94B in which the secondopener/closer 94 is slid to open the shutters 21 and 22 is antiparallelto the disc cartridge inserting direction 1A. Accordingly, if aprotrusion that engages with the second opener/closer 94 is provided fora disc drive, that protrusion engages with the second opener/closer 94and opens the shutters 21 and 22 of the disc cartridge 317 while thisdisc cartridge 317 is going to be inserted into the disc drive. Thus, asimplified shutter opening/closing mechanism may be provided for thedisc drive.

Embodiment 18

Hereinafter, a disc cartridge 318 according to an eighteenth specificpreferred embodiment of the present invention will be described withreference to FIGS. 98 through 101. In FIGS. 98 through 101, each memberof the disc cartridge 318 of the eighteenth preferred embodiment, havingsubstantially the same function as the counterpart of the disc cartridge316 of the sixteenth preferred embodiment described above, is identifiedby the same reference numeral.

As shown in FIG. 98, the disc cartridge 318 of this eighteenth preferredembodiment includes a second opener/closer 96 on its second side surface10 q instead of the second opener/closer 93 of the disc cartridge 316 ofthe sixteenth preferred embodiment described above.

As can be seen from FIG. 99, the second opener/closer 96 is a beltmember that is connected to the disc holder 21 a of the shutter 21. Thisbelt member 96 has a protrusion 96 a at one end thereof. And theprotrusion 96 a can slide along the opening 11 r of the lower shell 11.Alternatively, the second opener/closer 96 may form an integral part ofthe shutter 21.

FIGS. 100 and 101 illustrate two states of the disc cartridge 318 inwhich the shutters 21 and 22 thereof are closed and opened,respectively. As already described for the sixteenth and seventeenthpreferred embodiments, the shutters 21 and 22 can be opened or closed bysliding the first opener/closer 22 t in the direction 22 w or in theopposite direction.

The shutters 21 and 22 may also be opened by using the secondopener/closer 96 in the following manner. First, the locking mechanism20 k is unlocked as shown in FIG. 100. Next, the protrusion 96 a of thesecond opener/closer 96 is slid in the direction indicated by the arrow96B. As a result of this operation, a force is applied to the shutter 21in such a direction as to rotate the end of the shutter 21 on the shafthole 21 u, i.e., to the direction indicated by the arrow 96C. Since theother shutter 22 is also moved synchronously with the shutter 21 by wayof the interlocking mechanism 20 c, these two shutters 21 and 22 exposethe head and chucking openings 11 h and 11 c. To close the shutters 21and 22, the protrusion 96 a of the second opener/closer 96 may be slidin the opposite direction.

Just like the disc cartridge 316 of the sixteenth preferred embodimentdescribed above, no matter whether the disc drive used is compatiblewith only a disc cartridge including a shutter opener/closer on a sidesurface that extends perpendicularly to the disc cartridge insertingdirection or only a disc cartridge including a shutter opener/closer ona side surface that extends parallelly to the disc cartridge insertingdirection, the disc drive can always read or write a signal from/on thedisc stored in the disc cartridge 318 of this preferred embodiment.

If the second opener/closer 96 forms an integral part of the shutter 21,the number of members that make up the disc cartridge 318 can bereduced. As a result, the disc cartridge can be manufactured at a lowercost or the manufacturing process thereof can be simplified.

In the sixteenth through eighteenth preferred embodiments of the presentinvention described above, the second opener/closer is provided on theleft-hand side with respect to the disc cartridge inserting direction.However, the location of the second opener/closer is not limited to theleft-hand side. Alternatively, the second opener/closer may be providedon the right-hand side 10 r of the disc cartridge 316 with respect tothe disc cartridge inserting direction as shown in FIG. 88. As anotheralternative, the second opener/closer may also be provided on thebackside 10 t of the disc cartridge 316 as shown in FIG. 88. In thatcase, the belt-shaped second opener/closer 96 of this eighteenthpreferred embodiment is preferably used because the disc cartridge 318can have the protrusion 96 a of the second opener/closer 96 on itsbackside without changing its details so much.

Embodiment 19

Hereinafter, a disc cartridge 319 according to a nineteenth specificpreferred embodiment of the present invention will be described withreference to FIGS. 102 and 103. In FIGS. 102 through 103, each member ofthe disc cartridge 319 of the nineteenth preferred embodiment, havingsubstantially the same function as the counterpart of the disc cartridge313 of the thirteenth preferred embodiment described above, isidentified by the same reference numeral.

The disc cartridge 319 of this preferred embodiment is characterized byproviding rotation stoppers 97 for the disc holders 21 b, 22 a and 22 band concave portions 89 for the shutters 21 and 22, respectively. Theconcave portions 89 are used to ultrasonic weld a nonwoven fabric to theshutters 21 and 22.

More specifically, the disc holders 21 b, 22 a and 22 b include holes 21q, 22 r and 22 q that engage with the rotation stoppers 97. As shown inFIG. 103, the rotation stoppers 97 partially protrude from the slopes 21b′, 22 a′ and 22 b′ of the disc holders 21 b, 22 a and 22 b and contactwith the outer edge of the disc 100 while the disc 100 is held by thedisc holders 21 a, 21 b, 22 a and 22 b. The rotation stoppers 97 arepreferably made of an elastic material that has a large coefficient offriction, e.g., rubber.

It should be noted that at least one of the disc holders 21 a, 21 b, 22a and 22 b should include the rotation stopper 97 to stop the unwantedrotation of the disc 100 sufficiently. However, to prevent theunintentional rotation of the disc 100 with more certainty, the threerotation stoppers 97 are preferably provided as shown in FIG. 102.

In this structure, while the disc 100 is held by the disc holders 21 a,21 b, 22 a and 22 b, the rotation stoppers 97 that are in tight contactwith the disc 100 do not allow the user to rotate the disc 100 soeasily. Accordingly, in such a state, even if the user tries to rotatethe disc 100 intentionally while pressing the disc 100 against theshutters 21 and 22, the disc 100 will not rotate so easily. Thus, evenif relatively stiff dust has adhered to the nonwoven fabric that coversthe shutters 21 and 22, the disc 100 will not get scratched by such dustbecause the user cannot rotate the disc 100 accidentally.

In addition, by providing the rotation stoppers 97, it is possible toprevent the disc 100 from moving inconstantly inside the disc storageportion.

As shown in FIG. 102, the shutters 21 and 22 include the concaveportions 89 to which a nonwoven fabric is ultrasonic welded to partiallycover the shutter surfaces that contact with the signal recording side100A of the disc 100. In the preferred embodiment illustrated in FIG.102, the concave portions 89 are formed so as to surround the outerperiphery of those portions of the shutters 21 and 22 that contact withthe signal recording side 100A. The concave portions 89 are also formedinside the outer periphery. However, the concave portions 89 may beformed in any regions other than those illustrated in FIG. 102 as longas the nonwoven fabric can be adhered to the shutters 21 and 22 just asintended. At these concave portions 89, the nonwoven fabric isultrasonic welded to the shutters 21 and 22. When the nonwoven fabric isultrasonic welded to the shutters 21 and 22, the nonwoven fabric mightbe partially cured or the resin material of the shutters 21 and 22 mightpartially protrude from the nonwoven fabric. Even so, those cured orprotruding portions are received by the concave portions 89 and do notscratch the signal recording side 100A of the disc 100. When a nonwovenfabric is attached to the shutters 21 and 22, these concave portions 89are preferably formed on the shutters 21 and 22 in any of the disccartridges according to the first through eighteenth preferredembodiments of the present invention described above.

Embodiment 20

Hereinafter, a disc cartridge 320 according to a twentieth specificpreferred embodiment of the present invention will be described withreference to the accompanying drawings.

First, the overall structure of the disc cartridge 320 will be outlinedwith reference to FIG. 104. The disc cartridge 320 includes lower shell11, upper shell 12, first shutter 21, second shutter 22, disc stopper23, shielding member 24 and rotational member 25. These members may bemade of a synthetic resin, for example. However, there is no need tomake all of these members of the same material. Instead, best materialsmay be selected for these members in view of the mechanical strengths orappearance required for them.

As shown in FIG. 104, the cartridge body 10 has an inner lower surface11 u. The inner lower surface 11 u has a chucking opening 11 c and ahead opening 11 h. The chucking opening 11 c allows a chucking member(e.g., a spindle motor for rotating the disc 100) to enter the disccartridge 320 externally. The head opening 11 h allows a head, whichreads and/or writes a signal (or information) from/on the signalrecording side 100A of the disc 100, to enter the disc cartridge 320 andaccess a target location on the disc 100. The head opening 11 h iscontinuous with the chucking opening 11 c and reaches one side surfaceof the lower shell 11. Also, another opening 11 r is provided on anotherside surface of the lower shell 11, which is adjacent to the sidesurface having the head opening 11 h.

As will be described in detail later, the inner lower surface 11 u hastwo grooves 11 e and 11 f that receive the respective ends of convexportions 25 e and 25 f provided for the rotational member 25. Thesegrooves 11 e and 11 f preferably do not reach the bottom of the innerlower surface 11 u. The inner lower surface 11 u further includes shaftholes 39 that receive shafts 37 and 38 provided for the first and secondshutters 21 and 22, respectively. These shaft holes 39 preferably do notreach the bottom of the inner lower surface 11 u, either. In thepreferred embodiment illustrated in FIG. 104, the shafts 37 and 38 areformed on the first and second shutters 21 and 22 and the shaft holes 39are formed on the lower shell 11. Alternatively, shaft holes may beformed on the first and second shutters 21 and 22 and shafts may beformed on the lower shell 11.

The lower shell 11 further includes two positioning holes 11 w intowhich the cartridge positioning pins of the disc drive are inserted.

The upper shell 12 includes a circular disc window 12 w, which expandsover the entire projection area of the disc 100. The disc window 12 w isdefined by a cylindrical inner side surface 12 i of the cartridge body10. The disc 100 can be inserted into the disc cartridge 320 throughthis disc window 12 w. The inner side surface 12 i has a notch 12 g.

The upper surface 12 d of the upper shell 12 also has a notch 12 j,which engages with the disc stopper 23. Although not shown, the discstopper 23 and the upper surface 12 d of the upper shell 12 are providedwith concavo/convex portions engaging with each other so that the discstopper 23 does not disengage itself from the upper shell 12 so easily.When the disc stopper 23 is fitted with the upper shell 12, a portion ofthe disc stopper 23 protrudes into the disc window 12 w. In thispreferred embodiment, to reduce the overall thickness of the cartridgebody as much as possible, the notch 12 j is formed by removing a portionof the upper shell 12 completely. However, if the disc cartridge mayhave a thickness somewhat greater than that of the illustrated one, aconcave portion may also be formed instead of the notch 12 j by removinga portion of the upper shell 12 incompletely, and a disc stopperengaging with such a concave portion may be prepared. For example, thenotch and the disc stopper 23 of the disc cartridge 308 of the eighthpreferred embodiment described above may be provided for the disccartridge 320 of this twentieth preferred embodiment.

Another disc stopper 12 s is provided as an integral part of the uppershell 12 so as to expand into the window 12 w. The disc stoppers 12 sand 23 are used to prevent the disc 100 mounted from dropping downthrough the disc window 12 w during the time the first and secondshutters 21 and 22 are opened and during the time the first and secondshutters 21 and 22 are closed. These disc stoppers 12 s and 23 areparticularly effective when this disc cartridge 320 is loaded into avertically mounted disc drive. To remove the disc 100 from this disccartridge 320, the disc stopper 23 needs to be disengaged and removedfrom the upper shell 12, and the disc 100 needs to be picked up fromaround the notch 12 j, for example. Optionally, three or more discstoppers may be provided and/or each of the disc stoppers may be formedin any other shape or disposed at any position other than thatillustrated in FIG. 104.

The upper and lower shells 12 and 11 are adhered, welded or joined(e.g., screwed up) together around their outer periphery, therebyforming a cartridge body 10. Also, the inner lower surface 11 u and theinner side surface 12 i of the cartridge body 10 together make up a discstorage portion for storing the disc 100 therein.

In the disc storage portion, the space defined by the inner side surface12 i is wide enough to allow the disc 100 to rotate freely thereinwithout contacting with the inner side surface 12 i. The top of the discstorage portion is opened as the disc window 12 w, and the first side100B of the disc 100 stored in the disc storage portion is exposedentirely inside the disc window 12 w. On the other hand, the secondside, i.e., the signal recording side 100A, of the disc 100 faces theinner lower surface 11 u.

By adopting such a structure, the cartridge 320 can be thinner than theconventional cartridge in which both sides of the disc are covered. Inaddition, the label side of the disc 100 can be displayed inside thedisc window 12 w and the user can check the contents of the disc 100that were printed on the label side (i.e., the first side) 100B.Moreover, by displaying the design of the label side, the disc cartridgeincluding the disc can also have a good design.

The first and second shutters 21 and 22 are provided on the inner lowersurface 11 u of the cartridge body 10. When the disc 100 is storedinside the disc cartridge 320, the first and second shutters 21 and 22are located between the signal recording side (i.e., the second side)100A of the disc 100 and the inner lower surface 11 u. The first andsecond shutters 21 and 22 have the shafts 37 and 38, respectively, whichare inserted into the shaft holes 39 of the lower shell 11. Thus, thefirst and second shutters 21 and 22 rotate on the shafts 37 and 38,thereby covering or exposing the head and chucking openings 11 h and 11c. When the first and second shutters 21 and 22 are opened, the secondside 100A of the disc 100 is partially exposed inside the head opening11 h.

The first and second shutters 21 and 22 are provided with notches so asto define a hole 20 h in a region that overlaps with the center hole 100h of the disc 100 stored in the disc storage portion when the first andsecond shutters 21 and 22 are closed. The notches of the first andsecond shutters 21 and 22 are surrounded with convex portions 21 w and22 w, respectively. When the first and second shutters 21 and 22 areclosed, these convex portions 21 w and 22 w are in close contact witheach other, thereby forming a ring 20 w that is adjacent to the innercircumference of the center hole 100 h of the disc 100. As alreadydescribed in detail for the twelfth preferred embodiment, the ring 20 wprevents the dust from reaching the signal recording side 100A of thedisc 100 by way of the center hole 100 h. Furthermore, the convexportions 21 w and 22 w have protrusions 35 and 36, respectively. That isto say, the top of the protrusions 35 and 36 is higher than that of theconvex portions 21 w and 22 w.

Furthermore, to hold the disc 100 in the disc storage portion while thefirst and second shutters 21 and 22 are closed, the first shutter 21includes a disc holder 21 b and the second shutter 22 includes discholders 22 a and 22 b. These disc holders 21 b, 22 a and 22 b work justlike the disc holders as described for the eighth through nineteenthpreferred embodiments described above. In the eighth through nineteenthpreferred embodiments, the first shutter 21 further includes the discholder 21 a. In this twentieth preferred embodiment, however, the firstshutter 21 includes a convex portion 27 a instead of the disc holder 21a. The convex portion 27 a is provided to prevent the side surface ofthe disc 100 from being exposed through the head opening 11 h, whichreaches one side surface of the lower shell 11, while the first andsecond shutters 21 and 22 are closed.

When closed, the first and second shutters 21 and 22 are not entirely incontact with each other along a line but have a plurality of contactportions that are not aligned with the line. More specifically, theshutters 21 and 22 have a first pair of contact portions 21 f and 22 fand a second pair of contact portions 21 g and 22 g. In this preferredembodiment, the contact portions 21 f and 22 f contact with each otherapproximately along the centerline of the disc cartridge 320. On theother hand, the contact portions 21 g and 22 g contact with each otheralong a line that defines a predetermined angle (e.g., approximately 15degrees to approximately 18 degrees) with the centerline of the disccartridge 320. The effects achieved by such a structure are alreadydescribed in detail for the thirteenth preferred embodiment. As alsodescribed for the thirteenth preferred embodiment, the contact portions21 g and 22 g partially overlap with each other in the thicknessdirection of the disc 100.

As will be described in detail later, the first and second shutters 21and 22 include guide grooves 27 e and 28 f that respectively engage withthe convex portions 25 e and 25 f of the rotational member 25. The guidegrooves 27 e and 28 f extend vertically through the first and secondshutters 21 and 22, respectively, so that the convex portions 25 e and25 f of the rotational member 25 can reach the grooves 11 e and 11 f,respectively.

The rotational member 25 includes a sidewall 25 i and a disc supportingportion 25 a that is connected to the bottom of the sidewall 25 i. Thesidewall 25 i has a cylindrical shape and has such a size as to surroundthe side surface of the disc 100 stored in the disc storage portion. Thesidewall 25 i is discontinued by three notches 25 d, 25 g and 25 h. Thedisc supporting portion 25 a has a flat ring shape including a notch 25c. As the first and second shutters 21 and 22 are opened, the rotationalmember 25 is rotated, thereby overlapping the notch 25 c with the headopening 11 h. A protrusion 25 m for moving the shielding member 24 isprovided near the notch 25 d.

As described above, the convex portions 25 e and 25 f, which protrudetoward the lower shell 11, are provided on the lower surface of the discsupporting portion 25 a. Furthermore, an opener/closer 25 j, whichengages with the shutter opening/closing mechanism of a disc drive, isprovided on the outer side surface of the sidewall 25 i. Alternatively,where the shutter opening/closing mechanism of the disc drive has a gearshape, a gear may be provided on the outer side surface of the sidewall25 i instead of the opener/closer 25 j.

The shielding member 24 is disposed inside the notch 12 g of the innerside surface 12 i of the cartridge body 10. The structure and operationof the shielding member 24 will be described in detail later.

The respective members of the disc cartridge 320 are assembled in such amanner as satisfy the vertical positional relationship shown in FIG.104. As a result, the lower and upper shells 11 and 12 are joinedtogether so that the first and second shutters 21 and 22 are disposed onthe lower shell II and that the rotational member 25 is located over theshutters 21 and 22.

FIG. 105 is a plan view illustrating the disc cartridge 320 with theupper shell 12 thereof removed. FIG. 106 is a cross-sectional view ofthe disc cartridge 320 as viewed along the line F-F shown in FIG. 105.The first and second shutters 21 and 22 are now closed.

As shown in FIG. 105, the disc holder 22 a of the second shutter 22holds the disc 100 thereon inside the notch 25 d of the rotationalmember 25. The disc 100 is also held by the disc holders 21 b and 22 bof the first and second shutters 21 and 22 inside the notches 25 g and25 h of the rotational member 25, respectively.

The opener/closer 25 j of the rotational member 25 is located inside theopening 11 r of the lower shell 11. The protrusions 35 and 36 of thefirst and second shutters 21 and 22 protrude into the center hole 100 hof the disc 100. The center of rotation of the rotational member 25 issubstantially aligned with the center of the disc 100. That is to say,the rotational member 25 is disposed inside the disc storage portion soas to rotate substantially around the center of the disc 100.

The shafts 37 and 38 of the first and second shutters 21 and 22 arelocated under the disc supporting portion 25 a of the rotational member25. As shown in FIG. 106, there is almost no gap between the top of thesidewall 25 i of the rotational member 25 and the bottom of the uppersurface 12 d of the upper shell 12, thus regulating the verticalmovement of the rotational member 25. Accordingly, the rotational member25 can effectively prevent the shafts 37 and 38 of the first and secondshutters 21 and 22 from being raised and disengaged from the shaft holes39 of the lower shell 11 when the first and second shutters 21 and 22rotate.

As shown in FIG. 106, the disc supporting portion 25 a of the rotationalmember 25 has a sloped upper surface 25 k, and therefore, the disc 100is in contact with only a portion of the upper surface 25 k of the discsupporting portion 25 a near the sidewall 25 i. In such a structure,even if the ring-shaped disc supporting portion 25 a has its widthincreased to increase the mechanical strength of the rotational member25, the upper surface 25 k is in contact with only a portion of thesignal recording side 100A of the disc 100 around its outer periphery.Thus, the signal recording area is hardly in contact with the discsupporting portion 25 a. It should be noted that the top of that portionof the disc supporting portion 25 a that is in contact with the disc 100is located at the same vertical level as the top of the convex portions21 w and 22 w of the first and second shutters 21 and 22.

Next, it will be described how the first and second shutters 21 and 22that is going to be closed or opened mount or dismount the disc 100thereon/therefrom. FIG. 107 is a plan view illustrating the respectivepositions of the first and second shutters 21 and 22 and the rotationalmember 25 in a state where the first and second shutters 21 and 22 areclosed. FIG. 108 is a cross-sectional view of the disc cartridge 320 asviewed along the line G-G shown in FIG. 107. FIG. 109 is a plan viewillustrating the respective positions of the first and second shutters21 and 22 and the rotational member 25 in a state where the first andsecond shutters 21 and 22 are opened. FIG. 110 is a cross-sectional viewof the disc cartridge 320 as viewed along the line H-H shown in FIG.109. In FIGS. 107 and 109, the disc 100 is indicated by the two-dotchain.

As shown in FIG. 107, while the first and second shutters 21 and 22 areclosed, the disc holders 21 b, 22 a and 22 b protrude through thenotches 25 g, 25 d and 25 h of the sidewall 25 i of the rotationalmember 25 toward the center of the disc 100, thereby holding the disc100 thereon. As shown in FIG. 108, the disc holders 22 a and 22 b havedownwardly tapered slopes 22 a′ and 22 b′ that are in contact with theouter edge of the first side 100B of the disc 100. Thus, the discholders 22 a and 22 b press the disc 100 not only toward the centerthereof but also toward the first and second shutters 21 and 22.Although not shown, the other disc holder 21 b is also in the samestate. As a result, a portion of the signal recording side 100A of thedisc 100 around the outer periphery thereof contacts with the discsupporting portion 25 a. Also, as already described for the twelfthpreferred embodiment, the convex portions 21 w and 22 w of the first andsecond shutters 21 and 22 contact with a portion of the signal recordingside 100A of the disc 100 near the center hole 100 h thereof (notshown). In this manner, the signal recording area on the signalrecording side 100A of the disc 100 is shut off from the open air by thedisc supporting portion 25 a of the rotational member 25 and by theconvex portions 21 w and 22 w of the first and second shutters 21 and22. Consequently, no dust or fine particles will be deposited on, or noscratches will be created on, the signal recording area.

The hole 20 h defined by the first and second shutters 21 and 22 has adiameter approximately equal to that of the center hole 100 h of thedisc 100. Accordingly, even if this disc cartridge 320 is left upsidedown with the first and second shutters 21 and 22 thereof closed, nopart of the signal recording side 100A of the disc 100 will be exposedinside the hole 20 h of the first and second shutters 21 and 22. Forthat reason, no dust or fine particles will be deposited on the signalrecording side 100A of the disc 100.

To open the first and second shutters 21 and 22, the opener/closer 25 jis engaged with the shutter opening/closing mechanism of the disc drive,and is turned to the direction indicated by the arrow 25A. Then, therotational member 25 starts to rotate inside the disc storage portionand the protrusions 25 e and 25 f also start to rotate around the centerof the disc 100. The protrusions 25 e and 25 f are engaged with theguide grooves 27 e and 28 f, respectively. Accordingly, the protrusions25 e and 25 f rotating go inside the guide grooves 27 e and 28 f in thedirections indicated by the arrows 27E and 28F, respectively, whilepressing the sidewalls of the guide grooves 27 e and 28 f. As thesidewalls of the guide grooves 27 e and 28 f are pressed by theprotrusions 25 e and 25 f, the first and second shutters 21 and 22rotate on the shafts 37 and 38 to the directions indicated by the arrows21A and 22A, respectively.

The disc holder 21 b also starts to rotate on the shaft 37 to thedirection indicated by the arrow 21A, while the disc holders 22 a and 22b start to rotate on the shaft 38 to the direction indicated by thearrow 22A. Thus, the disc holders 21 b, 22 a and 22 b go away from thedisc 100 and release the disc 100.

As the first and second shutters 21 and 22 are opened, the protrusions35 and 36 on the first and second shutters 21 and 22 also rotate to thedirections 21A and 22A, respectively. In the meantime, the disc 100 doesnot move. Accordingly, the protrusions 35 and 36 contact with thenon-signal recording area 100 e on the signal recording side 100A of thedisc 100. The protrusions 35 and 36 are located at a vertical levelhigher than that of the convex portions 21 w and 22 w. Thus, while theprotrusions 35 and 36 are in contact with the signal recording side100A, the convex portions 21 w and 22 w are out of contact with thesignal recording side 100A. Consequently, it is possible to prevent theconvex portions 21 w and 22 w from scratching the signal recording side100A, or the signal recording area thereof, in particular.

As the rotational member 25 is rotated to a certain degree, theprotrusions 25 e and 25 f will soon reach the ends of their guidegrooves 27 e and 28 f, respectively, as shown in FIG. 109. Then, thefirst and second shutters 21 and 22 will be fully opened to expose thehead and chucking openings 11 h and 11 c entirely.

At that time, the notch 25 c of the disc supporting portion 25 a of therotational member 25 is aligned with the head opening 11 h, and no partof the disc supporting portion 25 a is exposed inside the head opening11 h. Accordingly, when the first and second shutters 21 and 22 arefully opened, the head of the disc drive can access the disc 100 easilyand is not interfered with by the rotational member 25.

Also, as shown in FIGS. 109 and 110, even when the first and secondshutters 21 and 22 are opened, the protrusions 35 and 36 of the firstand second shutters 21 and 22 are still in contact with the non-signalrecording area 100 e on the signal recording side 100A of the disc 100.Thus, the signal recording area will not get scratched by theprotrusions 35 and 36.

To close the shutters 21 and 22, the respective members should be movedin the opposite directions. That is to say, as the first and secondshutters 21 and 22 are closed, the disc holders 21 b, 22 a and 22 b aregetting closer to the disc 100 and eventually hold the disc 100 thereon.These operations have already been described in detail for the eighththrough thirteenth preferred embodiments, and the description thereofwill be omitted herein.

Next, the structure and operation of the shielding member 24 will bedescribed. As shown in FIG. 111, the shielding member 24 includes asidewall 24 d and a pair of shafts 24 b provided at the ends of thesidewall 24 d. At the bottom of the sidewall 24 d, a first contactingportion 24 a is provided. The first contacting portion 24 a needs tocontact with the outer side surface of the disc 100 and has a curvedsurface having the same radius of curvature as the outer side surface ofthe disc 100. The backside of the sidewall 24 d is a second contactingportion 24 f. An arm 24 c is provided near each of the shafts 24 b andhas a third contacting portion 24 e at the end thereof.

As shown in FIG. 112, the shielding member 24 is disposed at such aposition that the shaft 24 b thereof is located between the uppersurface 12 d of the upper shell 12 and the sidewall 25 i of therotational member 25. As indicated by the arrow 24A, the shieldingmember 24 can swing on the shaft 24 b. A line that connects therespective centers of the shafts 24 b together is parallel to a tangentline defined with respect to the disc 100 and is located at a verticallevel higher than the first side 100B of the disc 100.

FIGS. 113 and 114 illustrate cross sections of the shielding member 24at one end and the center thereof while the first and second shutters 21and 22 are closed. As shown in FIGS. 113 and 114, the sidewall 24 d ispressed toward the center of the disc 100 so that the convex portion 25m of the rotational member 25 contacts with the second contactingportion 24 f of the shielding member 24 and that the first contactingportion 24 a contacts with the outer side surface of the disc 100. Thus,no dust or dirt will reach the signal recording side 100A of the disc100 by way of the notch 25 c of the disc supporting portion 25 a (seeFIG. 104). In this manner, the disc supporting portion 25 a and theshielding member 24 are in contact with the outer periphery of the disc100 continuously, thereby preventing the dust or dirt from reaching thesignal recording side 100A.

As the rotational member 25 is rotated to open the first and secondshutters 21 and 22, the convex portion 25 m of the rotational member 25goes away from the shielding member 24. As a result, no force is appliedto the shielding member 24 toward the disc 100 anymore.

As the first and second shutters 21 and 22 are further opened and as therotational member 25 is further rotated, the outer side surface of thesidewall 25 i of the rotational member 25 will soon contact with thethird contacting portion 24 e of the shielding member 24, therebypressing the sidewall 24 d outward. FIGS. 115 and 116 illustrate crosssections of the shielding member 24 at one end and the center thereof.As shown in FIG. 115, the outer side surface of the disc 100 has beenout of contact with the first contacting portion 24 a of the shieldingmember 24. As a result, the disc 100 is now rotatable inside the discstorage portion.

In this manner, the shielding member 24 swings as the rotational member25 is rotated, thereby alternately coming into contact with the outerside surface of the disc 100 and out of contact with the outer sidesurface of the disc 100 to allow the disc 100 to rotate freely.

As described above, in this preferred embodiment, the label side 100B ofthe disc 100 is displayed inside the disc cartridge 320. Thus, the disccartridge 320 can have a good design and a reduced thickness.

In addition, the first and second shutters 21 and 22 can be opened andclosed by rotating the rotational member 25. While the shutters 21 and22 are closed, the disc 100 can be held firmly by the disc holders 21 b,22 a and 22 b.

Furthermore, while the disc 100 is held inside the disc storage portion,the label side 100B of the disc 100 is exposed. Even so, the discsupporting portion 25 a of the rotational member 25, the protrusions 21w and 22 w of the first and second shutters 21 and 22, and the shieldingmember 24 interlocked with the rotational member 25 together protect thesignal recording side 100A of the disc 100 from dust, dirt or scratches.

In the twentieth preferred embodiment described above, the opening 11 ris provided on one side surface of the lower shell 11 so that theopener/closer 25 j for use to rotate the rotational member 25 isoperated on the side surface that is adjacent to another side surfacethereof including the head opening 11 h. Alternatively, theopener/closer 25 j may be provided on any other side surface of thecartridge body 10. As another alternative, a plurality of opener/closersmay be provided as well. For example, the opener/closer 25 j of thepreferred embodiment described above may be used as a firstopener/closer and a protrusion may be provided as a second opener/closerfor the sidewall 25 i of the rotational member 25 so as to be locatedinside the head opening 11 h. Optionally, as shown in FIG. 105, aprotrusion 49 may be provided as a second opener/closer near the discholder 22 a of the second shutter 22 so that the second shutter 22 canbe operated directly. In that case, as the second shutter 22 is moved,the rotational member 25 rotates, thereby moving the first shutter 21synchronously.

In the twentieth preferred embodiment described above, the shieldingmember 24 prevents dust from reaching the signal recording side 100A ofthe disc 100 by way of the notch 25 c of the disc supporting portion 25a. Alternatively, any other structure may be used to prevent dust fromentering the disc cartridge 320 through the notch 25 c.

For example, as schematically illustrated in FIG. 117, the notch 12 g ofthe inner side surface 12 i of the cartridge body 10 may be closed up byextending the inner side surface 12 i, and the disc holder 22 b of thesecond shutter 22 (not shown) may be disposed at a position that issymmetrical to the notch 12 g with respect to the center of the disc100. Just like the disc holder of the thirteenth preferred embodimentdescribed above, the disc holder 22 b needs to be movable toward thecenter of the disc 100 and an elastic force needs to be applied to thedisc holder 22 b toward the center of the disc 100, too. As anotheralternative, as in the disc holder of the nineteenth preferredembodiment described above, an elastic member may be provided for aportion of the disc holder 22 b that contacts with the disc 100 so thatthe elastic force applied therefrom presses the disc 100 toward thecenter thereof as shown in FIG. 118.

Specifically, such a disc holder 22 b contacts with the disc 100 andholds it thereon, thereby pressing the outer side surface of the disc100 toward the notch 25 c of the inner side surface 12 i of thecartridge body 10. The sizes of the disc storage portion and the disc100 are almost equal to each other. Accordingly, the radius of curvatureof the inner side surface 12 i is approximately equal to that of theouter side surface of the disc 100. As a result, the outer side surfaceof the disc 100 closely contact with the inner side surface 12 i of thecartridge body 10. Thus, the inner side surface 12 i and the discsupporting portion 25 a together prevent dust from reaching the signalrecording side 100A of the disc 100.

Such a structure needs no shielding member 24, thus simplifying thestructure of the disc cartridge.

Embodiment 21

Hereinafter, a disc cartridge 321 according to a twenty-first specificpreferred embodiment of the present invention will be described.

FIG. 119 is an exploded perspective view of the disc cartridge 321 ofthe twenty-first preferred embodiment. The disc cartridge 321 of thistwenty-first preferred embodiment is different from the disc cartridge320 of the twentieth preferred embodiment shown in FIG. 104 in that thedisc cartridge 321 includes a disc stopper 55 of a different shape and aremoval history hole 11 n on the lower shell 11 thereof. Thus, thefollowing description of the twenty-first preferred embodiment will befocused on the disc stopper 55 and the removal history hole 11 n.

As shown in FIG. 119, the disc stopper 55 is provided near a sidesurface of the cartridge body, consisting of the upper and lower shells12 and 11, so as to face another side surface of the cartridge bodyhaving the head opening 11 h. A shaft 55 a is provided near one end ofthe longer side of the disc stopper 55, while the other end thereofincludes a latching portion 55 d with a protrusion 55 e.

The upper shell 12 includes a shaft hole 12 m to receive the shaft 55 aof the disc stopper 55, an opening 12 p into which the latching portion55 d is inserted, and another hole 12 n to receive the protrusion 55 eof the latching portion 55 d. The upper shell 12 also includes arecessed portion 12 k so that the upper surface of the disc stopper 55is leveled with the upper surface 12 d of the upper shell 12 when thedisc stopper 55 is attached to the upper shell 12. The shaft hole 12 mand the opening 12 p are formed in the recessed portion 12 k. While thedisc stopper 55 is protruding into the disc window 12 w and over thedisc 100 stored, the protrusion 55 e of the latching portion 55 d isinserted into the hole 12 n, thereby fixing the disc stopper 55 onto theupper shell 12.

The lower shell 11 includes the removal history hole 11 n. FIG. 120illustrates the removal history hole 11 n and its surrounding members toa larger scale. As shown in FIG. 120, the removal history hole 11 n isalmost covered with a cap member 56. Specifically, the cap member 56 isconnected to the inner sidewall of the removal history hole 11 n by wayof connectors 56 a. The cap member 56 has a columnar (or pin) shape andincludes a protrusion 56 b at the top thereof.

The center of the removal history hole 11 n is aligned with that of theshaft hole 12 m of the upper shell 12 and that of the shaft 55 a of thedisc stopper 55. As will be described in detail later, the cap member 56is engaged with the disc stopper 55. Accordingly, when the disc stopper55 is rotated on its shaft 55 a, a rotational force is applied to thecap member 56 in such a direction as to rotate the cap member 56 aroundits axis 56 c. As a result, the connectors 56 a are snapped off, the capmember 56 drops off from the lower shell 11, and the removal historyhole 11 n is fully opened.

When the disc cartridge 321 is manufactured, the disc 100 is stored inthe disc storage portion that is defined by the inner side surface 12 iof the upper shell 12. Thereafter, when the user rotates the discstopper 55 to remove the disc 100 from the disc cartridge 321, the capmember 56 will drop off and the removal history hole 11 n will beopened. Once the cap member 56 has been eliminated, the removal historyhole 11 n remains open even if another disc 100 is stored in the disccartridge 321 by operating the disc stopper 55. In other words, as longas the removal history hole 11 n is closed with the cap member 56, thedisc 100 stored in the disc cartridge 321 should be the disc that wasoriginally stored there during the manufacturing process of the disccartridge 321. On the other hand, if the removal history hole 11 n isopen, then the disc 100 stored in the disc cartridge 321 might bedifferent from the original disc that was stored there during themanufacturing process of the disc cartridge 321.

A disc drive to be loaded with this disc cartridge 321 senses the openedor closed state of this removal history hole 11 n, thereby controllingthe read or write operation in accordance with the result. For example,suppose the disc cartridge 321 manufactured should store a disc to beread from or written to in compliance with only a predeterminedstandard. In that case, if the disc drive finds the removal history hole11 n of the disc cartridge 321 closed, the disc drive recognizes thedisc stored in the disc cartridge 321 as readable or writable incompliance with the predetermined standard. Then, the disc drive canquickly perform a read or write operation on the disc in compliance withthat standard. On the other hand, if the disc drive finds the removalhistory hole 11 n of the disc cartridge 321 opened, the disc drivesenses the disc stored in the disc cartridge 321 as an unknown type. Inthat case, to recognize the type of the disc that is stored in the disccartridge 321, the disc drive applies various test signals to the discfirst. Next, in accordance with the test results, the disc drive readsor writes a signal from/on the disc under optimized conditions.

Hereinafter, the structure of the disc stopper 55 and the operation ofexchanging the original disc 100 for a different one will be describedin further detail.

FIG. 121 illustrates a state in which the disc stopper 55 protrudes overthe disc 100 to prevent the disc 100 from dropping through the discwindow 12 w of the upper shell 12. It is in such a state that the disccartridge 321 is either stored or inserted into a disc drive. FIGS. 122and 123 are cross-sectional views illustrating portions of the disccartridge 321 around the shaft 55 a and the latching portion 55 d,respectively, as viewed along the line J-J shown in FIG. 121. FIG. 124is a cross-sectional view illustrating portions of the disc cartridge321 as viewed along the line K-K shown in FIG. 121.

As shown in FIG. 121, the disc stopper 55 is opposed to another discstopper 12 s that protrudes from the upper shell 12 toward the center ofthe disc window 12 w. The disc stopper 55 has an arched concave sidesurface 55 f along the length thereof.

As shown in FIG. 122, the upper shell 12 includes a cylindrical boss 12q, inside which the shaft hole 12 m is defined. The shaft 55 a of thedisc stopper 55 is inserted into the shaft hole 12 m as described above.The shaft 55 a includes a protrusion 55p at the bottom thereof so as notto be disengaged from the shaft hole 12 m easily. Also, inside the shaft55 a, an inner space having an inside diameter that is approximatelyequal to the diameter of the removal history hole 11 n is defined. Thecap member 56 is stored inside that inner space. The protrusion 56 b ofthe cap member 56 is fitted with a concave portion 55 b of the discstopper 55. The center of the shaft 55 a of the disc stopper 55 isaligned with the axis of rotation 56 c of the cap member 56. Also, asdescribed above, the cap member 56 is connected to the inner sidewall ofthe removal history hole 11 n by way of the connectors 56 a. Theconnectors 56 a are thinner than the bottom of the lower shell 11.

As shown in FIG. 123, the latching portion 55 d at the other end of thedisc stopper 55 is inserted into the opening 12 p of the upper shell 12and in contact with the back surface of the upper shell 12. Theprotrusion 55 e, provided at the end of the latching portion 55 d, isfitted with the hole 12 n of the upper shell 12. The disc stopper 55further includes a bridge portion 55 f with a reduced thickness so thatthe latching portion 55 d is partially deformed elastically when theprotrusion 55 e is depressed in the direction indicated by the arrow 55Ain FIG. 123. Furthermore, the latching portion 55 d of the disc stopper55 and its associated contact surface of the upper shell 12 are providedwith stepped portions 55 g and 12 o, respectively, which engage witheach other. These stepped portions 55 g and 12 o are provided to preventthe latching portion 55 d and its surrounding portions from being raisedover the upper shell 12 when the disc stopper 55 is rotated.

To remove the disc 100 from the disc cartridge 321, the protrusion 55 ethat is engaged with the hole 12 n of the upper shell 12 is depressed inthe direction 55A as shown in FIGS. 123 and 124, and at the same time,the disc stopper 55 is rotated to the direction indicated by the arrow55B shown in FIG. 121. Then, as shown in FIG. 124, the bridge portion 55f of the latching portion 55 d is deformed elastically and the latchingportion 55 d slides while the top of the protrusion 55 e keeps contactwith a slope 12 v on the back surface of the upper shell 12. Since theslope 12 v is provided on the back surface of the upper shell 12, thelatching portion 55 d can easily reach the dashed-line location shown inFIG. 124 even if no great force is applied thereto along the slope 12 v.To make the elastically deformed bridge portion 55 f of the latchingportion 55 d recover its original shape, when the latching portion 55 dreaches this position, the top of the protrusion 55 e is located at thesame vertical level as it was when engaged with the hole 12 n.

In the meantime, the disc stopper 55 rotates to the direction 55B aroundthe center 55 c of the shaft 55 a thereof as shown in FIG. 122. As aresult, a force that rotates the cap member 56 to the direction 55Baround its axis of rotation 56 c is applied to the cap member 56,thereby snapping the connectors 56 a off and dropping the cap member 56off.

FIG. 125 illustrates a state where the disc stopper 55 has moved to sucha position as allowing the user to remove the disc 100 from the disccartridge 321. At this point in time, the latching portion 55 d hasalready contacted with the inner side surface of the upper shell 12 asshown in FIG. 124, and therefore, the disc stopper 55 can no longer berotated to the direction 55B.

As shown in FIG. 125, just a portion of the disc stopper 55 stillprotrudes into the disc window 12 w. However, if the disc 100 isslightly moved toward the disc stopper 12 s, the disc stopper 55 willnot be located over the disc 100 anymore. Then, the user can remove thedisc 100 from the disc cartridge 321 by gripping the disc 100 with afinger laid on the center hole 100 h thereof and lifting the edge of thedisc 100 from around the disc stopper 55 on the upper shell 12.

FIGS. 126 and 127 are cross-sectional views illustrating portions of thedisc cartridge 321 around the shaft 55 a and the latching portion 55 d,respectively, as viewed along the line J-J shown in FIG. 125. Asdescribed above, while the disc stopper 55 is being rotated, the capmember 56 drops off. Accordingly, when the disc stopper 55 has moved tothe limit, the removal history hole 11 n will be fully opened as shownin FIG. 126. Also, the protrusion 55 e of the latching portion 55 dengages with a recessed portion 12 r of the upper shell 12 as shown inFIG. 127. Thus, the elastically deformed bridge portion 55 f of thelatching portion 55 d recovers its original shape.

After the originally stored disc 100 is removed from the disc cartridge321, another disc 100 is stored in the disc cartridge 321 and then thedisc stopper 55 is rotated in the direction opposite to the arroweddirection 55B. When the disc stopper 55 gets to its original positionshown in FIG. 121, the protrusion 55 e of the latching portion 55 d isengaged with the hole 12 n of the upper shell 12 again and the discstopper 55 is fixed onto the upper shell 12 again.

To replace the disc 100 with still another disc, the disc stopper 55 maybe operated just as described above. However, since the cap member 56has already been removed, no cap member 56 will be dropped off by thedisc stopper 55 rotating.

In the disc cartridge 321 of this twenty-first preferred embodiment, thedisc stopper 55 has the arched concave side surface 55 f. Thus, even ifthe disc stopper 55 is not rotated so much, the disc stopper 55 can soonstop protruding over the disc 100. Also, since the disc stopper 55 isrotated to just a small degree, the latching portion 55 d of the discstopper 55 can keep contacted and engaged with the upper shell 12.Accordingly, even when the disc 100 is removed from the disc cartridge321, both ends of the disc stopper 55 still can keep contact with theupper shell 12 and the disc stopper 55 can maintain sufficientmechanical strength. Thus, even if the user dropped the disc cartridge321 by mistake or pressed the disc stopper 55 too strongly in removingthe disc 100 therefrom, the disc stopper 55 would not be broken.

In addition, according to this preferred embodiment, when the discstopper 55 is rotated, the removal history hole 11 n is opened.Accordingly, unlike the conventional disc cartridge, the user does nothave to snap off the tab of the history hole.

Furthermore, in the preferred embodiment described above, the cap member56 has a columnar shape. Alternatively, the cap member 56 may also haveany other shape as long as the cap member 56 can be connected to thelower shell 11 in such a manner as to cover the removal history hole 11n at least partially and can be removed as the disc stopper 55 rotates.For example, the cap member may include: a tab provided for the removalhistory hole 11 n; and an auxiliary member, which is provided betweenthe disc stopper 55 and the tab and snaps the tab off as the discstopper 55 rotates.

Also, in the preferred embodiment described above, the disc stopper 55is moved from a first position, at which the disc 100 is held tight soas not to drop from the disc cartridge 321, to a second position, atwhich the disc 100 is ready to remove from the disc cartridge 321, orvice versa, by rotating the disc stopper 55 parallelly to the disc 100.Alternatively, the disc stopper 55 may be moved in a differentdirection.

FIGS. 128 and 129 illustrate an alternative disc stopper 57 that slidesparallelly to the side surfaces of the disc cartridge 321. The discstopper 57 also has an arched concave side surface 57 f along the lengththereof. Specifically, FIG. 128 illustrates a state where the disc 100is held by the disc stopper 57. As shown in FIG. 128, in such a state,the disc stopper 57 is partially protruded over the disc 100. To removethe disc 100, the disc stopper 57 is moved in the direction indicated bythe arrow 57A (i.e., vertically to the longer side of the disc stopper57) as shown in FIG. 129. The side surfaces 57 a of the disc stopper 57are preferably provided with convex or concave portions that engage withthe upper shell 12 so that the disc stopper 57 is not disengaged fromthe upper shell 12 so easily.

The side surface 57 f of the disc stopper 57 is also arched andrecessed. Thus, just by moving the disc stopper 57 only slightly, thedisc stopper 57 can soon stop protruding over the disc 100. For thatreason, the disc 100 can be removed from the disc cartridge 321 whilemost of the disc stopper 57 keeps contact with the upper shell 12. As aresult, even when the discs 100 are exchanged, the disc stopper 57 doesnot lose its mechanical strength at all.

FIGS. 130 and 131 illustrate another alternative disc stopper 58, whichrotates on a shaft 58 a that is secured to the upper shell 12 at bothends of its longer side. In this alternative preferred embodiment, anelastic force is preferably applied from a spring, for example, to thedisc stopper 58 so that the disc stopper 58 keeps contact with the uppershell 12 as shown in FIG. 130. If necessary, the disc stopper 58 may berotated to the position shown in FIG. 131. However, since the discstopper 58 also has an arched concave side surface 58 f along the lengththereof, the disc 100 may be removed just by rotating the disc stopper58 slightly from the position shown in FIG. 130.

If the disc stopper 57 or 58 is provided for the disc cartridge 321, thedisc cartridge 321 may have a mechanism that removes the cap member asthe disc stopper 57 or 58 slides or rotates. Alternatively, the capmember that covers the removal history hole may not be interlocked withthe disc stopper 57 or 58. In that case, the disc cartridge may have amechanism that allows the disc stopper 57 or 58 to slide or rotate onlyafter the user has removed the cap member.

Embodiment 22

Hereinafter, a disc cartridge 322 according to a twenty-second specificpreferred embodiment of the present invention will be described.

FIG. 132 is a plan view illustrating the disc cartridge 322 of thetwenty-second preferred embodiment. FIG. 133 is a cross-sectional viewof the disc cartridge 322 as viewed along the line L-L shown in FIG.132. Just like the disc cartridge of the twentieth preferred embodimentas already described with reference to FIGS. 117 and 118, the disccartridge 322 can also prevent dust from entering the disc cartridge 322through the notch 25 c of the disc supporting portion 25 a without usingany shielding member. Although not shown in detail in FIG. 132, the disccartridge 322 also includes the first and second shutters 21 and 22,rotational member 25 and disc stopper 55 as already described for thetwentieth and twenty-first preferred embodiments. Each of these membersmay have the same structure as the counterpart of the twentieth ortwenty-first preferred embodiment described above.

In the disc cartridges 320 and 321 of the twentieth and twenty-firstpreferred embodiments shown in FIGS. 104 and 119, respectively, thesidewall 12 i of the upper shell 12 includes the notch 12 g, which islocated at the same position as the notch 25 c of the disc supportingportion 25 a while the first and second shutters 21 and 22 are closed.

Meanwhile, in the disc cartridge 322 of this twenty-second preferredembodiment, the sidewall 12 i does not have the notch 12 g but iscontinuous around the circumference of the disc 100. Also, as shown inFIG. 134, an extended sidewall 12 i′ is provided under the sidewall 12 iso as to contact with the outer side surface of the disc 100. Theextended sidewall 12 i′ is located at a position corresponding to thenotch 12 g.

The sidewall 12 i defines the disc window 12 w, and therefore has agreater radius of curvature than the disc 100. On the other hand, theextended sidewall 12 i′ has the same radius of curvature as the disc 100as shown in FIG. 135. As shown in FIG. 132, the center of the cylinderthat is defined by the sidewall 12 i is aligned with the center C1 ofthe disc storage portion. Meanwhile, the center of the curvature that isdefined by the extended sidewall 12 i′ is aligned with a point C2. Thatis to say, the point C2 is offset from the point C1. It should be notedthat the sidewall 25 i of the rotational member 25 defines a cylinder,of which the center is aligned with the center C1 of the disc storageportion, and rotates around the point C1.

Also, the disc holder 22 b holds the disc 100 thereon such that thecenter of the disc 100 is aligned with the point C2. Although only onedisc holder 22 b is illustrated in FIG. 132, the two other disc holders21 b and 22 a (not shown) also hold the disc 100 thereon so that thecenter of the disc 100 is aligned with the point C2. In such a position,the disc supporting portion 25 a supports the disc 100 thereon withoutcontacting with the signal recording side (i.e., the back surface) ofthe disc 100. Accordingly, the center of the disc supporting portion 25a is also offset from the point C1. The distance between the points C1and C2 is changeable with the radius of the cylinder defined by thesidewall 12 i and the radius of the disc 100. For example, if the disc100 has a diameter of 5 inches, the distance between the points C1 andC2 is preferably from about 0.5 mm to about 1.5 mm. The reason is asfollows. Specifically, if the distance is smaller than about 0.5 mm,then the disc 100 rotating might contact with the sidewall 12 i becausethe disc 100 will flutter when the disc 100 is rotated inside the disccartridge 322 that has been loaded into the disc drive. However, if thedistance between the points C1 and C2 is greater than about 1.5 mm, thenthe gap between the disc 100 and the sidewall 12 f disc storage portionwill be so wide that a lot of dust or other dirt might enter the disccartridge 322 through the gap.

FIG. 137 is a cross-sectional view illustrating the disc holder 22 b andits surrounding portions of the disc cartridge 322 as viewed along theline L-L shown in FIG. 132. As already described for the twentiethpreferred embodiment, the upper surface 25 k of the disc supportingportion 25 a is sloped, and the disc 100 contacts with only a portion ofthe upper surface 25 k of the disc supporting portion 25 a near thesidewall 25 i (not shown in FIG. 137) of the rotational member 25. Inthis preferred embodiment, that portion of the upper surface 25 k of thedisc supporting portion 25 a around the sidewall 25 i is parallel to thebottom of the lower shell 11. Accordingly, while the first and secondshutters 21 and 22 are closed so that the disc 100 gets held by the discholders 21 b, 22 a (not shown) and 22 b, the disc 100 contacts with thedisc supporting portion 25 a in this region 25 b. The innercircumference of the region 25 b in which the disc supporting portion 25a contacts with the disc 100 is defined by the dashed circle 25 n asshown in FIG. 132.

As shown in FIG. 132, the region 25 b of the disc supporting portion 25a is located almost around the outer periphery of the disc 100 butdiscontinued by the notch 25 c. Also, the inner circumference 25 n ofthe region 25 b defines a circle of which the center is aligned with thepoint C2. On the other hand, the outer circumference of the region 25 bis defined by the outer circumference of the disc 100. Accordingly, theregion 25 b is a notched ringlike region that is defined by twoconcentric circles having their centers aligned with the point C2 andthat is discontinued by the notch 25 c.

While the first and second shutters 21 and 22 (not shown in FIG. 132)are closed so that the disc 100 gets held by the disc holders 21 b, 22 a(not shown) and 22 b of the first and second shutters 21 and 22, thecenter of the disc 100 is aligned with the point C2. Also, since theradius of curvature of the disc 100 is equal to that of the extendedsidewall 12 i′, the outer side surface of the disc 100 comes into tightcontact with the extended sidewall 12 i′ at the position where the notch12 g exists in other disc cartridges. In other words, the center of thedisc 100 held by the disc holders 21 b, 22 a and 22 b is offset from thecenter of the disc storage portion so that the outer side surface of thedisc 100 comes into contact with, and gets held by, the extendedsidewall 12 i′.

Also, while the first and second shutters 21 and 22 (not shown in FIG.132) are closed, the center of the notched ringlike region 25 b, inwhich the disc supporting portion 25 a and the disc 100 contact witheach other, is also offset from the center of the disc storage portion.Accordingly, the signal recording side (i.e., the back surface) of thedisc 100 contacts with the disc supporting portion 25 a around the outerperiphery thereof and the outer side surface of the disc 100 closelycontacts with the extended sidewall 12 i′ where the disc supportingportion 25 a is discontinued by the notch 25 c.

On the other hand, around the center hole 100 h, the disc 100 is incontact with the convex portions 21 w and 22 w of the first and secondshutters 21 and 22 as already described for the twentieth preferredembodiment. Thus, the signal recording area of the disc 100 iscompletely shut off from the air, and no dust will be deposited on thesignal recording area of the disc 100.

Also, as shown in FIGS. 136 and 137, the disc holder 22 b of the secondshutter 22 of the disc cartridge 322 has a tapered bottom 26 c, while arecessed portion 11 x is provided for the lower shell 11 to receive thebottom 26 c of the disc holder 22 b. Accordingly, if the thickness orthe diameter of the disc 100 is not quite equal to, but slightly greaterthan, the standard one, then a portion 26 b of the second shutter 22 isdeformed elastically near the end of the recessed portion 11 x of thelower shell 11 as shown in FIG. 137. As a result, the sloped portion 22b′ of the disc holder 22 b contacts with the outer edge of the disc 100and the first and second shutters 21 and 22 can firmly hold the disc 100thereon without allowing the disc 100 to move inconstantly. Also, as thesecond shutter 22 is deformed elastically, the disc holder 22 b appliesan elastic force to the disc 100 toward the center thereof.Consequently, the disc 100 is pressed against, and comes into closercontact with, the extended sidewall 12 i′ as shown in FIGS. 132 and 134.Then, the unwanted deposition of dust on the signal recording area ofthe disc 100 can be prevented with even more certainty.

To get the disc 100 held just as intended irrespective of the variationin thickness or diameter of the disc 100, the disc cartridge 322 may bedesigned such that the second shutter 22 is slightly deformedelastically as shown in FIG. 137 when the thickness or the diameter ofthe disc 100 to be held is approximately equal to the center value ofits standard range and that the second shutter 22 is hardly deformedelastically as shown in FIG. 136 when the thickness or the diameter ofthe disc 100 to be held is approximately equal to the lower limit ofthat range.

As described above, according to this preferred embodiment, no dust willbe deposited on the signal recording area of the disc 100 even if noshielding member 24 is provided. That is to say, neither the shieldingmember 24 nor the mechanism for interlocking the shielding member 24with the rotational member 25 is needed, thus simplifying the structureof the disc cartridge significantly.

Embodiment 23

Hereinafter, a disc cartridge 323 according to a twenty-third specificpreferred embodiment of the present invention will be described.

The disc cartridge according to any of various preferred embodiments ofthe present invention described above stores a disc therein with oneside of the disc exposed unlike the conventional disc cartridge. Thus,the disc cartridge of the present invention can be thinner than theconventional one. Also, since the label side of the disc is displayed,the overall disc cartridge can have a good design.

However, since one side of the disc is supposed to be exposed insidethis disc cartridge, the user may touch the label side of the disc.Accordingly, a careless user might press the label side of the disc toostrongly. Thus, the disc cartridge of this type should hold the disc insuch a manner as to prevent the signal recording side of the disc fromgetting scratched or the disc itself from being deformed even in such asituation. In view of these potential unfavorable situations, thepresent inventors carried out an intensive research on how the discshould be held to have its signal recording side protected fromscratches, for example.

FIG. 138 illustrates a holding structure 59 (e.g., the disc supportingportion 25 a) for holding the disc 100 thereon and a space to beprovided under the signal recording area 100 d of the disc 100 so thatthe signal recording area 100 d will not get scratched by the holdingstructure 59 even if the disc 100 is pressed by the user too strongly.It should be noted that the sizes of some portions of the holdingstructure 59 are not to scale in FIG. 138 so as to make the features ofthe holding structure 59, which defines that space, clearlyunderstandable. Accordingly, the aspect ratio illustrated in FIG. 138 isdifferent from the actual one.

If plenty of space was allowed under the disc 100, the height of thespace had only to be slightly greater than the maximum flexure of thedisc 100. This is because, in that case, the disc 100 would nevercontact with the holding structure 59 no matter how much the disc 100was deformed. However, a disc cartridge with such an ample space wouldbe too thick. So the space under the disc 100 should actually beminimized. To minimize the space, the disc 100 needs to be held so as tohave as small flexure as possible. And to reduce the flexure, portionsof the disc 100 to be held by the holding structure 59 are preferably asclose to the signal recording area 100 d of the disc 100 as possible. Asshown in FIG. 138, the portions of the holding structure 59, on whichthe signal recording side 100A of the disc 100 is supported, are definedby an inner radius Rin and an outer radius Rout. That is to say, thedisc 100 is held not only by the inside portion of the holding structure59 that is located inside the inner radius Rin but also by the outsideportion of the holding structure 59 that is located outside of the outerradius Rout. The “inner radius Rin” is herein supposed to be a distancefrom the center of the disc 100 to a point that is located closer to thecenter of the disc 100 than, and defined near, the inner periphery ofthe signal recording area 100 d. On the other hand, the “outer radiusRout” is herein supposed to be a distance from the center of the disc100 to a point that is located closer to the outer edge of the disc 100than, and defined near, the outer periphery of the signal recording area100 d. As described above, these two points that define the inner andouter radii Rin and Rout are as close to the signal recording area 100 das possible. For example, if the disc 100 has a diameter of about 5inches (i.e., a radius of about 60 mm), then the inner radius Rin ispreferably about 20 mm and the outer radius Rout is preferably about 59mm.

The space 69 b to be provided under the disc 100 to prevent the signalrecording area 100 d from getting scratched is defined in the followingmanner. First, the height (or the depth) 5 (mm) of the space 69 b isdefined. Next, three circles 69 d, 69 e and 69 f are defined.Specifically, the circle 69 d has a radius that is equal to the outerradius Rout and is defined on the signal recording side 100A; the circle69 e has a radius obtained by (Rout—1.2 S) and is defined on a planethat is parallel to, and 0.3 S mm separated from, the signal recordingside 100A; and the circle 69 f has a radius obtained by (Rout—16.2 S)and is defined on a plane that is parallel to, and 5 mm separated from,the signal recording side 100A. A truncated cone, of which the top andbottom are defined by the circles 69 d and 69 e, respectively, has aside surface 59 a, while another truncated cone, of which the top andbottom are defined by the circles 69 e and 69 f, respectively, has aside surface 59 b.

A circular cylinder is also defined so as to have a circular bottom withthe radius Rin as measured from the center of the disc 100 and a sidesurface 59 d with the height (or depth) S as measured from the signalrecording side 10A. The space 69 b to be provided under the signalrecording area 100 d is obtained by removing the circular cylinder,defined by the side surface 59 d, from the two-stepped truncated conedefined by the side surfaces 59 a and 59 b.

The S value defines the height of the space 69 b. Accordingly, thegreater the S value, the less likely the signal recording area 100 dgets scratched even if the disc 100 is deformed. However, as the S valueis increased, the disc cartridge increases its thickness. Thus, to makea thin disc cartridge, the S value is preferably as small as possible.The present inventors discovered and confirmed via experiments that evenan S value of about 1 mm was great enough to protect the signalrecording area 100 d of the disc 100 from scratches as long as theflexure of the disc 100 was caused by a pressure that was manuallyapplied by the user.

On the other hand, a clamp area 100 e′ of the disc 100 preferably doesnot contact with the holding structure 59 within the region defined bythe inner radius Rin. The reason is as follows. When the disc cartridge323 is loaded into a disc drive to read and/or write a signal from/onthe disc 100, the clamp area 100 e′ will contact with a turntable or aclamper. Accordingly, if this area 100 e′ has been scratched orpartially covered with dust, then the disc 100 cannot get chucked asintended. The clamp area 100 e′ is defined by two concentric circlesthat have diameters of about 22 mm and about 33 mm, respectively, andhave their centers aligned with that of the disc 100. The clamp area 100e′ accounts for just a small percentage of the overall area of the disc100. Thus, even if the user presses the disc 100 from over the clamparea 100 e′, the disc 100 will be hardly bent. For that reason, only ifa space 69 a is provided so as to contact with the entire clamp area 100e′, the space 69 a may have any height (or depth).

FIG. 139 schematically illustrates how much the disc 100 is deformed ifthe space 69 b is provided under the disc 100 with the S value set to 1mm and a pressure is applied onto the disc 100 toward the space 69 b.The present inventors discovered and confirmed via experiments that thepressure that was applied manually onto the disc 100 by the user neverexceeded 3 kg. The present inventors also discovered that even when themaximum pressure of 3 kg was applied, the disc 100 was bent fully withinthe space 69 b and never contacted with the side surface 59 a or 59 b.

In this case, the space 69 b defined has minimum required dimensions toprevent the signal recording area 100 d of the disc 100 from gettingscratched. Accordingly, a greater space may be provided under the signalrecording area 100 d of the disc 100. That is to say, the space 69 b maybe provided beyond the side surfaces 59 a and 59 b as shown in FIGS. 140and 141. In that case, however, to sufficiently increase the mechanicalstrength of the outside portion of the holding structure 59 to hold theouter periphery of the disc 100 thereon, a reinforced portion 59′ or 59″is preferably provided adjacent to the outside portion. The sidesurfaces 59 a and 59 b can be used effectively to determine theallowable shapes of those reinforced portions 59′ and 59″.

Hereinafter, a disc cartridge that was designed in view of theseconsiderations will be described specifically. FIG. 142 is a plan viewof the disc cartridge 323. FIG. 143 is a cross-sectional view thereof asviewed along the line P-P shown in FIG. 142. FIG. 144 is an explodedperspective view of the disc cartridge 323. In the disc cartridge 323 ofthis twenty-third preferred embodiment, each member that is equivalentto the counterpart of the disc cartridge according to the twentieth,twenty-first or twenty-second preferred embodiment described above isidentified by the same reference numeral.

Just like the disc cartridge 322 of the twenty-second preferredembodiment described above, the disc cartridge 323 has no shieldingmember but holds the disc 100 thereon by bringing the outer side surfaceof the disc 100 into contact with the sidewall 12 i of the upper shell12.

More specifically, while the first and second shutters 21 and 22 areclosed, the disc cartridge 323 gets the disc 100 held by the disc holder21 b of the first shutter 21 and the disc holders 22 a and 22 b of thesecond shutter 22 as shown in FIGS. 142 and 144. In this case, the outerside surface of the disc 100 contacts with the sidewall 12 i of theupper shell 12 where the notch 25 c of the rotational member 25 islocated. Also, the center of the disc 100 is aligned with the point C2.The inner circumference of the region, in which the disc supportingportion 25 a of the rotational member 25 contacts with the disc 100, hasits center aligned with the point C2 so that the region contacts withthe signal recording side 100A of the disc 100 equally. On the otherhand, the center of the sidewall 25 i of the rotational member 25 isaligned with the point C1.

As shown in FIGS. 142 and 144, a ring 20 w, consisting of convexportions 21 w and 22 w, is provided around the hole 20 h that is definedby the first and second shutters 21 and 22 of the disc cartridge 323.The hole 20 h corresponds to the center hole 100 h of the disc 100.Another pair of convex portions 35 d and 36 d is provided so as to beseparated from the ring 20 w by a predetermined distance. The uppersurface of the convex portions 35 d and 36 d is leveled with that of theconvex portions 21 w and 22 w. When the first and second shutters 21 and22 are closed, the convex portions 35 d and 36 d define a continuousring 20 d that holds a portion of the disc 100 near the signal recordingarea thereof. The concave portion that is created between these tworings 20 w and 20 d defines the space 69 a. When the disc 100 is heldthereon, the clamp area of the disc 100 is located right over the space69 a.

Also, as shown in FIG. 143, the convex portion 36 d, second shutter 22and disc supporting portion 25 a of the rotational member 25 aredesigned such that the space 69 b shown in FIG. 138 is provided underthe disc 100 when the disc 100 is held on this disc cartridge 323.Although not shown in FIG. 143, the other convex portion 35 d and thefirst shutter 21 are also designed for the same purpose. Furthermore,the disc cartridge 323 is also designed such that a gap of 1 mm or moreis provided between the disc 100 mounted and the first and secondshutters 21 and 22. Also, the disc supporting portion 25 a is locatedoutside of the space 69 b shown in FIG. 138 (i.e., under the sidesurfaces 59 a and 59 b that define the space 69 b) and does not obstructthe space 69 b at all.

By providing the space 69 b shown in FIG. 138 under the disc 100 in thismanner, the signal recording area of the disc 100 stored in the disccartridge 323 can be protected just as intended even if the disc 100 ispressed by the user too strongly.

It is to be noted that the disc cartridge 323 may be adapted to a disc100 having a so-called “stack ring” or “stacking ring” in the vicinityof the clamp area 100 e′. As shown in FIG. 138 the stack ring is aprotruding ring 100 p provided on the signal recording side 100A of thedisc 100. The protruding ring 100 p has a circular shape coaxiallyformed with the center hole 100 h. The protruding ring 100 p preventsthe signal recording area 100 d from contacting with a flat plane in thecase where the disc is placed on the flat plane with the signalrecording side 100A down. The protruding ring 100 p is located betweenthe clamp area 100 e′ and the center hole 100 h and is apart from theedge of the center hole 100 h by 0.1 mm or more. The protruding ring 100p has a width of about 1 mm in the radial direction and a height of 0.05to 0.5 mm from the surface of the signal recording area 10 d. Morespecifically, in one type of the disc 100, a diameter of center hole 100h is 15 mm, the clamp area 100 e′ is defined between a circle of a 22 mmdiameter and a circle of a 33 mm diameter, the protruding ring 100 p islocated in a region defined by a circle of a 17.5 mm diameter and acircle of a 22 mm diameter, the width of the protruding ring 100 p isabout 1 mm, and the height the protruding ring 100 p is 0.3 mm or less.Alternatively, the protruding ring 100 p may be located between theclamp area 100 e′ and the signal recording area 100 d and is apart fromthe edge of the clamp area 100 e′ by 2 mm or less.

In this case, the disc holder 21 b of the first shutter 21 and the discholders 22 a and 22 b of the second shutter 22 hold the disc 100 in sucha manner as not to contact with neither a clamp area 100 e′ nor theprotruding ring lop. Therefore, the space 69 a defined by the rings 20 wand 20 d is made enough large so as to include the protruding ring 100p. More specifically, when the first and second shutters 21 and 22 areclosed, the disc holder 21 b of the first shutter 21 and the discholders 22 a and 22 b of the second shutter 22 hold the disc 100 in sucha manner as not to contact with neither the clamp area 100 e′ nor theregion which is located between the clamp area 100 e′ and the centerhole 100 h and which is apart from the edge of the center hole 100 h by0.1 mm or more, or in such a manner as not to contact with neither theclamp area 100 e′ nor the region which is located between the clamp area100 e′ and the signal recording area 100 d and which is apart from theedge of the clamp area 100 e′ by 2 mm or less. In the case of theaforementioned specific type of the disc 100, the space 69 a shouldinclude the region defined by a first circle of the 17.5 mm diameter anda second circle which is smaller than the first circle by 0.1 to 0.3 mm.It is to be noted that the space 69 a may be continuous one region forthe clamp area 100 e′ and the protruding ring 100 p or may be consist ofseparate regions for the clamp area 100 e′ and the protruding ring 100p.

The disc cartridge 323 of this preferred embodiment further includesother structures that are specially designed to increase the mechanicalstrength of its members, selectively attach one of two types of discstoppers, and increase the dustproofness, respectively, for the purposeof increasing the usefulness of this disc cartridge 323. Hereinafter,those structures will be described in detail.

First, the structure for increasing the mechanical strength of themembers of the disc cartridge 323 will be described. As shown in FIGS.142 and 144, while the first and second shutters 21 and 22 are closed,the disc holders 21 b, 22 a and 22 b apply an elastic force to the disc100 toward the center thereof. This is because the connecting portionbetween the first shutter 21 and the disc holder 21 b and the connectingportions between the second shutter 22 and the disc holders 22 a and 22b are deformed elastically by the disc 100.

However, if the user dropped the disc cartridge 323 by mistake or triedto rotate the disc 100 forcibly inside the disc cartridge 323 byapplying a force onto the exposed side 100B of the disc 100, then aforce could be applied from the center of the disc 100 to the discholders 21 b, 22 a and 22 b outward. And if such a force were greatenough, the connecting portion between the first shutter 21 and the discholder 21 b and the connecting portions between the second shutter 22and the disc holders 22 a and 22 b might be snapped. Among other things,the portion that connects the disc holder 21 b to the first shutter 21and the portion that connects the disc holder 22 b to the second shutter22 are too narrow to sufficiently resist the forces that are applied inthe directions indicated by the arrows 21B and 22B, respectively, inFIG. 142.

In view of this potential snapping of those connecting portions, thesidewall 25 i of the rotational member 25 of this disc cartridge 323 isformed such that the cross sections 65 a and 65 b of its notches 25 gand 25 h are not parallel to the radial direction of the disc 100 (i.e.,the directions 21B and 22B) but face the disc storage portion 10 d.Accordingly, while the shutters 21 and 22 are closed, the displacementof the disc holders 21 b and 22 b in the directions 21B and 22B isregulated by the cross sections 65 a and 65 b, respectively, so as notto exceed their predetermined limits.

By providing these cross sections 65 a and 65 b, the disc holders 21 band 22 b would not be snapped off even if the user dropped the disccartridge 323 by mistake or tried to move the disc holders 21 b and 22 boutward intentionally. Also, even if some force is applied in such adirection as to open the first and second shutters 21 and 22accidentally while the shutters 21 and 22 are supposed to be closed, thedisc holders 21 b and 22 b, which are going to move along with theshutters 21 and 22 being opened, will soon contact with the crosssections 65 a and 65 b, respectively. As a result, the first and secondshutters 21 and 22 will not open accidentally. Thus, it is possible tominimize the unintentional movement of the first and second shutters 21and 22 being closed.

Also, if the user attempts to open the first and second shutters 21 and22 intentionally, then the first and second shutters 21 and 22 are goingto rotate around the shaft holes 37 and 38, respectively, as shown inFIG. 142. Then, the inner sidewalls of the respective guide grooves 27 eand 28 f of the first and second shutters 21 and 22 are going to rotatethe convex portions 25 e and 25 f of the rotational member 25 to thedirections 25E and 25F around the shaft holes 37 and 38, respectively,as shown in FIG. 142.

In this case, if the ends of the guide grooves 27 e and 28 f wereelongated in the directions 25E and 25F or if the guide grooves 27 e and28 f allowed the convex portions 25 e and 25 f to move in the directions25E and 25F, respectively, then the first and second shutters 21 and 22would move inconstantly.

To eliminate such an inconstant movement of the first and secondshutters 21 and 22, those ends of the guide grooves 27 e and 28 f, wherethe convex portions 25 e and 25 f are located while the shutters 21 and22 are closed, are elongated in the directions indicated by the arrows27E and 28F, which substantially cross the arrows 25E and 25F at rightangles. As shown in FIG. 142, the directions 27E and 28F aresubstantially parallel to the lines that connect the convex portions 25e and 25 f to the shaft holes 37 and 38, respectively.

Furthermore, as shown in FIG. 144, the lower shell 11 is provided with araised portion 33 b and the rotational member 25 is provided with araised portion 25 w. The heights of these raised portions 33 b and 25 ware approximately equal to the thickness of the first and secondshutters 21 and 22. The raised portion 33 b contacts with the backsurface of the disc supporting portion 25 a of the rotational member 25.The raised portion 25 w engages with a concave portion 33 c that isformed on the inner lower surface 11 u of the cartridge body 10. Theseraised portions 33 b and 25 w are provided to support the portions ofthe rotational member 25 that are not in contact with the first orsecond shutter 21 or 22. Thus, even those portions of the rotationalmember 25 that are not in contact with the first or second shutter 21 or22 would not be deformed or lose contact with the disc 100.

As already described for the fourteenth preferred embodiment, the discholder 22 a includes the first and second portions 122 a and 222 a andthe upper surface of the first portion 122 a is higher than that of thesecond portion 222 a. Also, the top of the first portion 122 a isinserted into a recessed portion 12 x that is provided on the backsurface of the upper shell 12. The recessed portion 12 x is providedalong a region where the top of the first portion 122 a passes as theshutters are going to be opened or closed.

As shown in FIGS. 142 and 144, the head opening 11 h is provided wherethe disc holder 22 a passes as the shutters are going to be opened orclosed, and reaches a side surface of the lower shell 11. Accordingly,when the cartridge body is formed by combining the lower and uppershells 11 and 12 together, the mechanical strength of the cartridge bodyaround the head opening 11 h should be secured only by the upper shell12.

In the disc cartridge 323, as the shutters are going to be closed, thefirst portion 122 a of the disc holder 22 a can grip the disc 100thereon just as intended as already described for the fourteenthpreferred embodiment. Also, since the upper surface of the secondportion 222 a of the disc holder 22 a is located at a low verticallevel, the upper shell 12 does not have to have a reduced thickness overthe second portion 222 a. Accordingly, the recessed region 12 x of theupper shell 12, where the first portion 122 a of the disc holder 22 apasses as the shutters are going to be opened or closed, should have areduced thickness but can be just a small portion of the overall uppershell 12. Thus, it is possible to prevent the mechanical strength of theoverall cartridge body from decreasing excessively around the headopening 11 h.

Furthermore, the disc cartridge 323 of this preferred embodiment has astructure of increasing the rigidity thereof while the shutters areclosed as described for the thirteenth preferred embodiment.

Specifically, as shown in FIGS. 145 and 146, the first and secondshutters 21 and 22 have two pairs of contact portions 21 f, 22 f′ and 21g′, 22 g′, which are discontinuous and separated from each other by thehole 20 h and each pair of which overlaps with each other vertically.That is to say, the first shutter 21 includes the contact portions 21 g′and 21 f′, while the second shutter 22 includes the contact portions 22g′ and 22 f′. FIGS. 146A and 146B are cross-sectional views of the firstand second shutters 21 and 22 as viewed along the lines N-N and O-Oshown in FIG. 145, respectively. In one pair of contact portions 21 g′and 22 g′ shown in FIG. 146A, while the shutters 21 and 22 are closed,the contact portion 21 g′ of the first shutter 21 is located over thecontact portion 22 g′ of the second shutter 22 in the thicknessdirection of the shutters 21 and 22. In the other pair of contactportions 21 f′ and 22 f′ shown in FIG. 146B, while the shutters 21 and22 are closed, the contact portion 21 f′ of the first shutter 21 islocated under the contact portion 22 f′ of the second shutter 22 in thethickness direction of the shutters 21 and 22.

Also, as shown in FIG. 146A, the edge of the contact portion 22 g′ ofthe second shutter 22 includes a convex portion 38 c that extends alongthe contact portion 22 g′. On the other hand, the first shutter 21includes a concave portion 37 c that engages with the convex portion 38c while the shutters 21 and 22 are closed.

Furthermore, as shown in FIG. 147, where the disc holder 22 a of thesecond shutter 22 contacts with the convex portion 27 a of the firstshutter 21, the convex portion 27 a includes a protrusion 37 a and thedisc holder 22 a includes a concave portion 38 a that engages with theprotrusion 37 a. Another concave portion 37 b is provided over theprotrusion 37 a. Another protrusion 38 b, which engages with the concaveportion 37 b, is provided over the concave portion 38 a. The protrusion37 a and the concave portion 37 b define another contact portion 37 e ofthe first shutter 21. On the other hand, the concave portion 38 a andthe protrusion 38 b define another contact portion 38 e of the secondshutter 22. These contact portions 37 e and 38 e of the first and secondshutters 21 and 22 will be herein referred to as a “third pair ofcontact portions”.

As described above, in the disc cartridge 323 of the twenty-thirdpreferred embodiment, two separate pairs of contact portions 21 g′, 22g′ and 21 f′, 22 f′ are provided for the first and second shutters 21and 22 and each pair of contact portions of the first and secondshutters 21 and 22 overlaps with each other in the thickness directionof the shutters. Also, the order in which the contact portions 21 g′ and22 g′ of the first pair overlap with each other is reverse to the orderin which the contact portions 21 f′ and 22 f′ of the second pair overlapwith each other. By utilizing such a structure, the first and secondshutters 21 and 22 closed will not be raised unintentionally, and thecontact portions thereof can have increased rigidity.

Also, by providing the concave portion 37 c and the convex portion 38 cfor the contact portions 21 g′ and 22 g′ of the first and secondshutters 21 and 22, respectively, the contact portions 21 g′ and 22 g′of the shutters 21 and 22 closed will not be easily disengaged from eachother due to the inconstant movement thereof, for example. In thismanner, the first and second shutters 21 and 22 can contact with eachother even more closely, thus increasing the dustproofness of the disccartridge around these contact portions of the shutters.

Furthermore, by providing the third pair of contact portions 37 e and 38e for the first and second shutters 21 and 22, respectively, the contactportions of the first and second shutters 21 and 22 closed can haveincreased rigidity. Also, the contact portion 21 g′ and the protrusion37 a of the first shutter 21 are sandwiched between the protrusion 38 band the contact portion 22 g′ of the second shutter 22. As a result, thecontact portions of the first and second shutters 21 and 22 closed canhave further increased rigidity.

Next, the structure that is specially designed to selectively attach oneof two types of disc stoppers to the disc cartridge 323 will bedescribed. As shown in FIG. 144, the upper shell 12 of the disccartridge 323 includes the shaft hole 12 m and another hole 12 m′.Either the disc stopper 55 or a disc stopper 59 can be fitted in theholes 12 m and 12 m′ as a means for preventing the disc 100 fromdropping down through the disc window 12 w. The disc stopper 55 of thedisc cartridge 323 of this twenty-third preferred embodiment has thesame structure as the disc stopper 55 of the disc cartridge 321 of thetwenty-first preferred embodiment described above. That is to say, byinserting the shaft 55 a into, and engaging it with, the shaft hole 12 mof the upper shell 12, the disc stopper 55 can rotate on the shaft 55 a.Then, as already described for the twenty-first preferred embodiment, aportion of the disc stopper 55 may be protruded into the disc window 12w, thereby preventing the disc 100 from dropping accidentally.Alternatively, if the disc stopper 55 is rotated to the position shownin FIG. 125, the disc 100 may be removed from the disc cartridge 323.

On the other hand, the disc stopper 59 includes protrusions 59 a and 59b. When the disc stopper 59 is attached to the upper shell 12, theprotrusions 59 a and 59 b of the disc stopper 59 are inserted into, andengaged with, the holes 12 m and 12 m′, respectively. Since the discstopper 59 is fixed onto the upper shell 12 at these two points, thedisc stopper 59 is not rotatable but always protrudes partially into thedisc window 12 w. That is to say, while the disc stopper 59 is attachedto the upper shell 12, the disc 100 stored in the disc cartridge 323 isnot removable.

In this manner, by providing the shaft hole 12 m and the hole 12 m′,which may be engaged with either the disc stopper 55 or the disc stopper59, as engaging means for the upper shell 12, one of these two discstoppers 55 and 59 may be selectively attached to the cartridge bodydepending on the necessity. That is to say, by adopting one of these twodisc stoppers 55 and 59 selectively, the resultant disc cartridge 323may or may not allow the user to remove the disc 100 that has been oncestored in the disc cartridge 323.

The disc cartridge 323 shown in FIG. 144 is illustrated as not includingthe removal history hole 11 n or the cap member 56 of the disc cartridge321 of the twenty-first preferred embodiment. However, the removalhistory hole 11 n and cap member 56 may be provided for the disccartridge 323. If the removal history hole 11 n, cap member 56 and discstopper 55 are provided for the disc cartridge 323, then the cap member56 will drop off as already described for the twenty-first preferredembodiment as the disc stopper 55 is rotated to remove the disc 100 fromthe disc cartridge 323. Then, the removal history hole 11 n will befully exposed. On the other hand, if the disc stopper 59 is attached tothe upper shell 12 instead of the disc stopper 55, then the disc 100cannot be removed by rotating the disc stopper 59. Accordingly, in thatcase, the removal history hole 11 n will be kept covered with the capmember 56.

Next, the structure of increasing the dustproofness of the disccartridge 323 will be described with reference to FIGS. 144, 145, 148and 149. As shown in FIG. 144, the chucking and head openings 11 c and11 h of the lower shell 11 are surrounded with a rim 33 a, which isindicated by the dashed lines in FIG. 145. FIG. 148 is a cross-sectionalview of the disc cartridge 323 as viewed along the line M-M shown inFIG. 145. As shown in FIG. 148, the back surfaces of the first andsecond shutters 21 and 22 include concave portions 37 d and 38 d,respectively, which engage with the rim 33 a.

The first and second shutters 21 and 22 rotate on the lower shell 11.Accordingly, as the first and second shutters 21 and 22 rotate, the dustthat has been deposited on the back surfaces of the first and secondshutters 21 and 22 would easily enter the cartridge body if there was agap between the first and second shutters 21 and 22 and the lower shell11. However, by filling the gap with this structure, almost no dust willenter the disc cartridge 323 from the chucking and head openings 11 cand 11 h.

Furthermore, as shown in FIG. 149, the contact portions of the first andsecond shutters 21 and 22 around the hole 20 h, which is defined by thefirst and second shutters 21 and 22 closed, are provided with mutuallyengaging concave and convex portions 35 a, 36 a and 35 b, 36 b. That isto say, the first shutter 21 includes the concave portions 35 a and 35 band the second shutter 22 includes the convex portions 36 a and 36 b.The convex portions 36 a and 36 b of the second shutter 22 protrude fromthe contact plane that is defined by the first and second shutters 21and 22 closed. Thus, no dust will enter the disc cartridge 323 from thehole 20 h and through the contact plane between the first and secondshutters 21 and 22.

In the twenty-third preferred embodiment described above, the discsupporting portion 25 a for holding the disc 100 thereon is provided forthe rotational member 25 to define the space 69 b shown in FIG. 138under the disc 100. Alternatively, any other structure may be adopted todefine the space 69 b shown in FIG. 138 under the disc 100. For example,as shown in FIG. 150, a disc supporting portion 25 a′ for holding theouter edge of the disc 100 may be provided for an alternative uppershell 12′. Even so, by forming the disc supporting portion 25 a′ andfirst and second shutters 21 and 22 in such shapes as to define thespace 69 b shown in FIG. 138 under the disc 100, the signal recordingarea of the disc 100 will not contact with the shutters or discsupporting portion of the disc cartridge even if the disc 100 is pressedby the user too strongly.

Embodiment 24

Hereinafter, a disc drive according to a twenty-fourth specificpreferred embodiment of the present invention will be described withreference to FIG. 151.

FIG. 151 is perspective view schematically illustrating a main portionof a disc drive 900 according to the twenty-fourth preferred embodiment.Any of the disc cartridges 301 through 323 according to the firstthrough twenty-third preferred embodiments of the present inventiondescribed above may be loaded into this disc drive 900. In the specificexample illustrated in FIG. 151, the disc cartridge 323 according to thetwenty-third preferred embodiment is loaded into this disc drive 900. InFIG. 151, the disc 100 is indicated by the dashed line.

As shown in FIG. 151, the disc drive 900 includes: a driver 902 forrotating the disc 100 that is stored inside the disc cartridge 323; anda head 908 for reading and/or writing a signal (or information) from/onthe disc 100.

The driver 902 includes a spindle motor 904 and a turntable 906 that isfitted with the shaft of the spindle motor 904. The spindle motor 904 issupported on a base 910. The head 908 is moved by an actuator (notshown) along a guide shaft 912.

The disc drive 900 further includes a damper 916 that is supported by anarm 914. Each of the turntable 906 and the damper 916 includes a magnetand a magnetic body, for example. As will be described later, the disc100 is sandwiched and held between the damper 916 and the turntable 906by utilizing the attraction between the magnets, and thereby mountedonto the turntable 906. In this manner, the driving force of the spindlemotor 904 can be transmitted to the disc 100 just as intended and thedisc 100 can be rotated without fluttering.

The disc cartridge 323 includes the opener/closer 25 j for opening andclosing the first and second shutters 21 and 22 on its side surface 10 rthat is parallel to the direction 1A in which the disc cartridge 323 isinserted into this disc drive 900. To operate this opener/closer 25 j,the disc drive 900 includes a shutter opening/closing mechanism 918 thatengages with the opener/closer 25 j to open and close the shutters 21and 22. The shutter opening/closing mechanism 918 is provided near theside surface 10 r of the disc cartridge 323 that has been loaded intothe disc drive 900. In FIG. 151, to illustrate the opener/closer 25 jclearly, the shutter opening/closing mechanism 918 is illustrated asbeing separated from the opener/closer 25 j. An actuator for use to movethe shutter opening/closing mechanism 918 is not illustrated in FIG.151, either.

It should be noted that the shutter opening/closing mechanism 918 needsto be located beside the shutter opener/closer of the disc cartridge tobe inserted into this disc drive 900. For example, if the disc cartridgeto be loaded has a shutter opener/closer on the side surface 10 pincluding the head opening 11 h as in the first or tenth preferredembodiment described above, then the shutter opening/closing mechanism918 should be provided near the side surface 10 p. On the other hand,when the disc cartridge according to any of the sixteenth througheighteenth preferred embodiments described above is loaded into the discdrive 900, the shutter opening/closing mechanism 918 may be providednear the side surface 10 q.

Optionally, two or more shutter opening/closing mechanisms 918 may beprovided for the same disc drive 900. For example, a second shutteropening/closing mechanism 918 may be additionally provided near the sidesurface 10 p of the disc cartridge 323 shown in FIG. 151 so that eitherthe disc cartridge 301 of the first preferred embodiment or the disccartridge 323 of the twenty-third preferred embodiment may be loadedinto this disc drive 900.

The shutter opening/closing mechanism 918 has such a structure as toengage with the opener/closer 25 j of the disc cartridge. In the disccartridge 323, the first and second shutters 21 and 22 are opened orclosed by sliding the opener/closer 25 j. Accordingly, the shutteropening/closing mechanism 918 should engage with the opener/closer 25 jand slide in the direction indicated by the arrow 1A. Where theopener/closer 25 j has a gear shape (i.e., when a disc cartridge havinga geared opener/closer is loaded as in the sixteenth preferredembodiment), the shutter opening/closing mechanism 918 also needs tohave a gear shape.

Posts 920 are provided on the base 910 to define a vertical level atwhich the disc cartridge 323 is supported. That is to say, the disccartridge 323 is supported on the top of the posts 920. Also,positioning pins 922 are further provided on the base 910 so as toengage with the positioning holes 11 w of the disc cartridge 323.

These posts 920 and positioning pins 922 function as a supportingstructure for disposing the disc cartridge 323 at a predeterminedposition with respect to the driver 902. Optionally, instead of theposts 920 and the positioning pins 922, a tray may be provided as analternative supporting structure for the disc drive 900. In that case,the tray may be drawn out to mount the disc cartridge 323 thereon andthen inserted into the disc drive 900 to load the disc 100 into the discdrive 900 and to dispose the disc cartridge 323 at a predeterminedposition with respect to the driver 902 and the head 908. As anotheralternative, the tray and the positioning pins 922 may be used incombination as the supporting structure.

Hereinafter, it will be described how this disc drive 900 operates.

First, the disc cartridge 323 that stores the disc 100 therein is loadedinto the disc drive 900. The disc cartridge 323 may be loaded eithermanually by the user or automatically by a loading mechanism (notshown). In the latter case, the loading mechanism may transport the disccartridge 323 from a disc cartridge insert slot (not shown) of the discdrive 900 to the position illustrated in FIG. 151. Then, the concaveportions 10 c or 10 e as described above for the first or sixteenthpreferred embodiment may be provided at the positions indicated by thearrows 926 in FIG. 151 and may be engaged with the loading mechanism.Alternatively, the tray may also be used as described above. In one ofthese methods, the disc cartridge 323 is disposed at a predeterminedposition with respect to the driver 902 and the head 908.

As another alternative, the concave portion 10 g as described above forthe first preferred embodiment or the slit 10 b as described above forthe sixteenth preferred embodiment may be provided at the position ofthe disc cartridge 323 as indicated by the arrow 928 or 930 in FIG. 151.In that case, the disc drive 900 may have a convex portion (not shown)that engages with the concave portion 10 g or the slit 10 b. Then, evenif the user tries to insert the disc cartridge 323 upside down or thewrong way round into this disc drive 900, the disc cartridge 323 isejected because interference should occur between the disc cartridge 323and the disc drive 900. In this manner, it is possible to prevent theuser from inserting the disc cartridge 323 into the disc drive 900erroneously.

When the disc cartridge 323 is disposed at the position shown in FIG.151, the shutter opening/closing mechanism 918 engages with theopener/closer 25 j, thereby sliding the opener/closer 25 j in thedirection opposite to that indicated by the arrow 1A. As a result, thefirst and second shutters 21 and 22 start to open to expose the head andchucking openings 11 h and 11 c in the end. Also, as already describedfor the twentieth preferred embodiment, the shutter opening/closingmechanism 918 makes the disc holders 21 b, 22 a and 22 b release thedisc 100 by way of the first and second shutters 21 and 22. Thus, thedisc 100 is released from the disc holders 21 b, 22 a and 22 b.Subsequently, the arm 914 holding the damper 916 thereon lowers, therebysandwiching and holding the disc 100 between the damper 916 and theturntable 906. Consequently, the disc 100 is mounted on the turntable906 so as to be rotatable inside the disc storage portion of the disccartridge 323.

Next, the disc 100 starts being rotated by the spindle motor 904. Then,the head 908 accesses the signal recording area of the disc 100 to reador write a signal from/on the disc 100.

To unload the disc cartridge 323 from the disc drive 900, first, the arm914 is raised, thereby separating the damper 916 from the disc 100.Next, the shutter opening/closing mechanism 918 is moved in thedirection indicated by the arrow 1A to slide the opener/closer 25 j. Asa result, the first and second shutters 21 and 22 are closed. As thefirst and second shutters 21 and 22 are going to be closed, the discholders grip the disc 100 thereon. And when the first and secondshutters 21 and 22 are completely closed, the disc holders hold the disc100 thereon. Thereafter, an unloading mechanism (not shown) ejects thedisc cartridge 323 from the disc drive 900.

Into the disc drive 900 shown in FIG. 151, the disc cartridge 323 isloaded horizontally. Alternatively, as already described for the firstor eighth preferred embodiment, the disc drive 900 may also be mountedvertically so that the disc cartridge is loaded thereto vertically. Thisis because even when the disc cartridge is loaded vertically into thedisc drive 900, the disc stoppers still can prevent the disc 100 fromdropping down from the disc storage portion.

In the first through twenty-third preferred embodiments described above,a nonwoven fabric is ultrasonic welded or adhered to the shutters.However, if the disc has some anti-scratching structure (e.g., if thesignal recording side of the disc is covered with a stiff hard coating),then the nonwoven fabric does not have to be attached thereto, but theshutters may directly contact with the disc. Also, not the entiresurface of the shutters has to contact with the signal recording side ofthe disc, but the shutters may have such a structure that at leastportion of the shutters contacts with the signal recording side of thedisc. That is to say, not the entire surface but just a portion of thesurface of the shutters may be in contact with the disc. In that case,some anti-scratching structure (e.g., a nonwoven fabric) may be providedfor only that portion contacting with the disc.

In the first through twenty-fourth preferred embodiments of the presentinvention described above, the disc 100 to be stored in the disccartridge has just one signal recording side 100A. However, asingle-sided disc like this is herein adopted for illustrative purposesonly. This is because the disc cartridge of the present invention hassuch a structure as to expose one side of the disc stored therein andbecause a single-sided disc is best suited to the disc cartridge of thattype. Thus, even a disc having two signal recording sides (i.e., adouble-sided disc) may be appropriately stored in the disc cartridge ofthe present invention and may be loaded into a disc drive to read orwrite a signal therefrom/thereon. It should be noted, however, thatwhere a double-sided disc is stored in the disc cartridge of the presentinvention, dust may be deposited on the exposed one of the two signalrecording sides. Accordingly, in that case, some mechanism forpreventing the unwanted dust deposition should be provided for the disccartridge.

Also, in the first through twenty-fourth preferred embodiments describedabove, the size of the disc 100 is not particularly specified. This isbecause the disc cartridge of the present invention may accommodate adisc having a size of 12 cm or any of various other sizes.

Furthermore, in the first through twenty-fourth preferred embodimentsdescribed above, the disc cartridge is illustrated as having an outerdimension that is slightly greater than the size of the disc. However,the size relationship between the disc and the disc cartridge is notlimited to the illustrated one. For example, even when the disccartridge has an outer dimension that is large enough to store a 12 cmdisc therein, the disc storage portion and the disc holders of the disccartridge may have their sizes and structures defined in such a manneras to store an 8 cm disc. Such a disc cartridge may be used as anadapter for getting read and write operations performed on an 8 cm discby a disc drive for a 12 cm disc.

The various features of the present invention as described for the firstthrough twenty-fourth preferred embodiments may be combinedappropriately. For example, the rotation stoppers as described for thenineteenth preferred embodiment may be provided for the disc cartridgeof the sixteenth preferred embodiment. Also, the recesses for use tocollect dust therein as described for the fifteenth preferred embodimentmay be provided for the disc cartridge of the sixteenth preferredembodiment. As can be seen, the first through twenty-fourth preferredembodiments of the present invention may be modified or combined innumerous other ways and not all of those possible combinations oralternatives have been described herein. However, it is quite possiblefor those skilled in the art to conceive and carry out those variousalternatives or combinations by reference to the description of thepresent application. Thus, it is intended by the appended claims tocover all of those modifications or combinations of the presentinvention that fall within the true spirit and scope of the presentinvention.

INDUSTRIAL APPLICABILITY

The disc cartridge according to various preferred embodiments of thepresent invention described above can be used particularly effectivelyto store a disc having only one signal recording side. The cartridgebody of the disc cartridge has such a structure as to cover only thesignal recording side of the disc and expose the other side thereof.Thus, the disc cartridge can have a reduced thickness. Also, theshutters of the disc cartridge are formed in such a shape as to coverthe openings on just one side of the disc cartridge. Accordingly, theshutters can have a simplified structure and can be formed at a lowercost. In addition, the disc holders of the disc cartridge hold a discthereon by pressing the disc against the shutters or the cartridge body.Thus, the disc will not move inconstantly inside the cartridge body andno dust will be deposited on the signal recording side of the disc.Furthermore, since the label side of the disc is displayed inside thedisc window, the disc cartridge can also have a good design.

Thus, the present invention provides a thinner and highly dustproof disccartridge of a good design that is applicable for use in various typesof disc drives.

It should be understood that the foregoing description is onlyillustrative of the invention. Various alternatives and modificationscan be devised by those skilled in the art without departing from theinvention. Accordingly, the present invention is intended to embrace allsuch alternatives, modifications and variances which fall within thescope of the appended claims.

It will be appreciated by those skilled in the art that changes could bemade to the embodiments described above without departing from the broadinventive concept thereof. It is understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications within the spirit and scope of thepresent invention as defined by the appended claims.

1. A disc cartridge comprising: a cartridge body including a discstorage portion, a chucking opening and a head opening, wherein the discstorage portion has a disc window and a bottom and stores a disc, havingfirst and second sides, therein so that the first side of the disc isexposed inside the disc window; the chucking opening is formed on thebottom of the disc storage portion so as to get the disc chuckedexternally; and the head opening is also formed on the bottom of thedisc storage portion so as to allow a head, which reads and/or writes asignal from/on the second side of the disc, to access the second side ofthe disc; at least a shutter, provided on the bottom of the disc storageportion, for exposing or covering the head opening; a rotational member,which is provided over the shutter inside the disc storage portion andwhich is interlocked with the shutter in such a manner as to open orclose the shutter when the rotational member rotates inside the discstorage portion; and a disc holder for holding the disc thereon so asnot to contact with a signal recording area on the second side of thedisc while the shutter is closed.
 2. The disc cartridge of claim 1,wherein first, second and third circles are defined so as to have radiiR1, R2 and R3, respectively, R1, R2 and R3 satisfy the inequalityR1>R2>R3 and the disc cartridge has a space in a first truncated cone,of which the bottom and top are defined by the first and second circles,respectively, and in a second truncated cone, of which the bottom andtop are defined by the second and third circles, respectively, where theradius R1 of the first circle is defined as a distance from the centerof the disc to a first point on the second side of the disc, the firstpoint being located closer to an outer edge of the disc than, anddefined near, the outer periphery of the signal recording area; thecenter of the second circle is located on a first plane and aligned withan axis that is defined perpendicularly to the center of the disc, thefirst plane being parallel to, and spaced apart by a predetermineddistance from under, the second side; and the center of the third circleis located on a second plane and aligned with the axis that is definedperpendicularly to the center of the disc, the second plane beingparallel to the second side and further spaced apart by anotherpredetermined distance from under, the first plane.
 3. The disccartridge of claim 2, wherein a distance from the center of the disc toa second point on the second side of the disc is Rin, where the secondpoint is located closer to the center of the disc than, and definednear, the inner periphery of the signal recording area while the shutteris closed; the distance from the center of the disc to the first pointon the second side of the disc is Rout, where the first point is locatedcloser to the outer edge of the disc than, and defined near, the outerperiphery of the signal recording area while the shutter is closed; aspace having a height S is provided under the second side of the disc;the first and second planes are defined so as to be spaced apart fromthe second side by a distance of 0.3 S and the distance S, respectively,the radii R1, R2 and R3 of the first, second and third circles are equalto Rout, (Rout-1.2S) and (Rout-16.2S), respectively and the space isobtained by removing a circular cylinder, having a bottom radius of Rinas measured from the center of the disc and the height S, from the firstand second truncated cones, where the bottom and top of the firsttruncated cone are defined by the first and second circles,respectively, and the bottom and top of the second truncated cone aredefined by the second and third circles, respectively.
 4. The disccartridge of claim 3, wherein the height S of the space is 1 mm, theradius Rin of the bottom of the circular cylinder is 20 mm, and theradius Rout of the first circle is 59 mm.
 5. The disc cartridge of claim3, wherein the rotational member includes: a disc supporting portion,which contacts with an outer periphery of the second side of the discwhile the shutter is closed and thereby holds the disc thereon; and anotch, which is provided for the disc supporting portion so as to belocated inside the head opening while the shutter is opened, and whereinthe disc storage portion includes a sidewall along an outer periphery ofthe bottom, and wherein the disc holder holds the disc thereon with thecenter of the disc offset from the center of the disc storage portionsuch that an outer side surface of the disc contacts with the sidewallof the disc storage portion at a position where the notch of therotational member is located while the shutter is closed.
 6. The disccartridge of claim 5, wherein the disc supporting portion of therotational member is located at such a position as not to obstruct thespace while the shutter is closed.
 7. The disc cartridge of claim 5,wherein the inner circumference of a region, in which the discsupporting portion of the rotational member contacts with the secondside of the disc, defines a circle that has its center offset from thecenter of the disc storage portion.
 8. The disc cartridge of claim 7,wherein while the shutter is closed, the center of the disc is alignedwith the center of the circle.
 9. The disc cartridge of claim 7, whereinwhile the shutter is closed, a distance between the center of the discand the center of the disc storage portion is about 0.5 mm to about 1.5mm.
 10. A disc cartridge comprising: a cartridge body including a discstorage portion, a chucking opening and a head opening, wherein the discstorage portion has a disc window and a bottom and stores a disc, havingfirst and second sides, therein so that the disc is rotatable in thedisc storage portion and that the first side of the disc is exposedinside the disc window; the chucking opening is formed on the bottom ofthe disc storage portion so as to get the disc chucked externally; andthe head opening is also formed on the bottom of the disc storageportion so as to allow a head, which reads and/or writes a signalfrom/on the second side of the disc, to access the second side of thedisc; first and second shutters, provided on the bottom of the discstorage portion, for exposing or covering the head opening; a rotationalmember, which is provided over the first and second shutters inside thedisc storage portion and which is interlocked with the first and secondshutters in such a manner as to open or close the first and secondshutters when the rotational member rotates inside the disc storageportion; and a disc holder for holding the disc thereon in such a manneras not to contact with a clamp area, which is provided on the secondside of the disc, while the first and second shutters are closed. 11.The disc cartridge of claim 10, wherein the disc holder holds the discin such a manner as not to contact with a protruding ring provided onthe second side of the disc in the vicinity clamp area.
 12. The disccartridge of claim 11, wherein when the first and second shutters areclosed, the disc holder holds the disc in such a manner as not tocontact with neither a clamp area nor a region which is located betweenthe clamp area and a center hole of the disc and which is apart from theedge of the center hole by 0.1 mm or more or in such a manner as not tocontact with neither a clamp area nor a region which is located betweenthe clamp area and the signal recording area and which is apart from theedge of the clamp area by 2 mm or less.
 13. A disc cartridge comprising:a cartridge body including a disc storage portion, a chucking openingand a head opening, wherein the disc storage portion has a disc windowand a bottom and stores a disc, having first and second sides, thereinso that the disc is rotatable in the disc storage portion and that thefirst side of the disc is exposed inside the disc window; the chuckingopening is formed on the bottom of the disc storage portion so as to getthe disc chucked externally; and the head opening is also formed on thebottom of the disc storage portion so as to allow a head, which readsand/or writes a signal from/on the second side of the disc, to accessthe second side of the disc; first and second shutters, provided on thebottom of the disc storage portion, for exposing or covering the headopening; and a rotational member, which is provided over the first andsecond shutters inside the disc storage portion and which is interlockedwith the first and second shutters in such a manner as to open or closethe first and second shutters when the rotational member rotates insidethe disc storage portion, wherein the first and second shutters havefirst and second pairs of contact portions in two separate regions, thecontact portions of each of the first and second pairs contacting andoverlapping with each other in a thickness direction, an order in whichthe contact portions of the first pair overlap with each other beingreverse to an order in which the contact portions of the second pairoverlap with each other.
 14. The disc cartridge of claim 13, wherein thefirst and second shutters further include a sidewall, which stands inthe vicinity of the first pair of contact portions, and a third pair ofcontact portions, which contacts and overlaps with each other in thethickness direction over the sidewall, one of the two contact portionsof the first pair and one of the two contact portions of the third pairof the first or second shutter contacting with, and sandwiching, theother contact portion of the first pair and the other contact portion ofthe third pair of the second or first shutter.
 15. A disc cartridgecomprising: a cartridge body including a disc storage portion, achucking opening and a head opening, wherein the disc storage portionhas a disc window and a bottom and stores a disc, having first andsecond sides, therein so that the disc is rotatable in the disc storageportion and that the first side of the disc is exposed inside the discwindow; the chucking opening is formed on the bottom of the disc storageportion so as to get the disc chucked externally; and the head openingis also formed on the bottom of the disc storage portion so as to allowa head, which reads and/or writes a signal from/on the second side ofthe disc, to access the second side of the disc; first and secondshutters, provided on the bottom of the disc storage portion, forexposing or covering the head opening; and a rotational member, which isprovided over the first and second shutters inside the disc storageportion and which is interlocked with the first and second shutters insuch a manner as to open or close the first and second shutters when therotational member rotates inside the disc storage portion, wherein thefirst and second shutters are closed to define a hole in a regioncorresponding to a center hole of the disc, and wherein a contactportion of one of the first and second shutters includes a convexportion around the hole, while a contact portion of the other shutterincludes a concave portion, which engages with the convex portion,around the hole.
 16. A disc cartridge comprising: a cartridge bodyincluding a disc storage portion, a chucking opening and a head opening,wherein the disc storage portion has a disc window and a bottom andstores a disc, having first and second sides, therein so that the discis rotatable in the disc storage portion and that the first side of thedisc is exposed inside the disc window; the chucking opening is formedon the bottom of the disc storage portion so as to get the disc chuckedexternally; and the head opening is also formed on the bottom of thedisc storage portion so as to allow a head, which reads and/or writes asignal from/on the second side of the disc, to access the second side ofthe disc; first and second shutters, provided on the bottom of the discstorage portion, for exposing or covering the head opening; and arotational member, which is provided over the first and second shuttersinside the disc storage portion and which is interlocked with the firstand second shutters in such a manner as to open or close the first andsecond shutters when the rotational member rotates inside the discstorage portion, wherein the first and second shutters include aplurality of disc holders that contact with an outer side surface of thedisc and a periphery of the outer side and that holds the disc thereonwhile the first and second shutters are closed, and wherein therotational member includes a sidewall that contacts with at least one ofthe disc holders in such a manner as to prevent the at least one discholder from being deformed in a radial direction of the disc while thefirst and second shutters are closed.
 17. A disc cartridge comprising: acartridge body including a disc storage portion, a chucking opening anda head opening, wherein the disc storage portion has a disc window and abottom and stores a disc, having first and second sides, therein so thatthe disc is rotatable in the disc storage portion and that the firstside of the disc is exposed inside the disc window; the chucking openingis formed on the bottom of the disc storage portion so as to get thedisc chucked externally; and the head opening is also formed on thebottom of the disc storage portion so as to allow a head, which readsand/or writes a signal from/on the second side of the disc, to accessthe second side of the disc; first and second shutters, provided on thebottom of the disc storage portion, for exposing or covering the headopening; and a rotational member, which is provided over the first andsecond shutters inside the disc storage portion and which is interlockedwith the first and second shutters in such a manner as to open or closethe first and second shutters when the rotational member rotates insidethe disc storage portion, wherein the cartridge body includes a rim,which is provided on the bottom of the disc storage portion so as tosurround the chucking and head openings, and wherein the first andsecond shutters include respective concave portions on their backsurfaces, which are opposed to the bottom of the disc storage portion,to receive the rim.
 18. A disc cartridge comprising: a cartridge bodyincluding a disc storage portion, a chucking opening and a head opening,wherein the disc storage portion has a disc window and a bottom andstores a disc, having first and second sides, therein so that the discis rotatable in the disc storage portion and that the first side of thedisc is exposed inside the disc window; the chucking opening is formedon the bottom of the disc storage portion so as to get the disc chuckedexternally; and the head opening is also formed on the bottom of thedisc storage portion so as to allow a head, which reads and/or writes asignal from/on the second side of the disc, to access the second side ofthe disc; first and second shutters, provided on the bottom of the discstorage portion, for exposing or covering the head opening; and arotational member, which is provided over the first and second shuttersinside the disc storage portion and which is interlocked with the firstand second shutters in such a manner as to open or close the first andsecond shutters when the rotational member rotates inside the discstorage portion, wherein the cartridge body includes engaging means thatis selectively engageable with a first or second disc stopper so thateach of the first and second disc stoppers is attachable to thecartridge body, the first disc stopper being movable from a firstposition, at which the first disc stopper protrudes partially over thedisc that is stored inside the disc storage portion, to a secondposition, at which the first disc stopper is not located over the disc,or vice versa, the second disc stopper being fixed at the firstposition.
 19. A disc cartridge comprising: a cartridge body including adisc storage portion, a chucking opening and a head opening, wherein thedisc storage portion has a disc window and a bottom and stores a disc,having first and second sides, therein so that the disc is rotatable inthe disc storage portion and that the first side of the disc is exposedinside the disc window; the chucking opening is formed on the bottom ofthe disc storage portion so as to get the disc chucked externally; andthe head opening is also formed on the bottom of the disc storageportion so as to allow a head, which reads and/or writes a signalfrom/on the second side of the disc, to access the second side of thedisc; first and second shutters, provided on the bottom of the discstorage portion, for exposing or covering the head opening; and arotational member, which is provided over the first and second shuttersinside the disc storage portion and which is interlocked with the firstand second shutters in such a manner as to open or close the first andsecond shutters when the rotational member rotates inside the discstorage portion, wherein the first and second shutters are disposed soas to be sandwiched between the rotational member and the bottom of thedisc storage portion, and wherein the cartridge body includes a raisedportion, which has a height that is approximately equal to the thicknessof the first and second shutters, on the bottom of the disc storageportion.